The OP is talking about using through-hole parts, so I\'m thinking this
isn\'t a production design.
On Friday, August 26, 2022 at 7:49:44 AM UTC-7, Phil Hobbs wrote:
Fred Bloggs wrote:
On Thursday, August 25, 2022 at 9:08:31 PM UTC-4, Ed Lee wrote:
On Thursday, August 25, 2022 at 5:49:01 PM UTC-7, legg wrote:
On Thu, 25 Aug 2022 15:35:53 +0100, Martin Brown
\'\'\'newspam\'\'\'@nonad.co.uk> wrote:
On 25/08/2022 14:49, Ed Lee wrote:
I am looking for 3x to 5x power output of typical TL432
(100mA). Is there a higher power equivalent part? If not, i
will probably put 3 to 5 of them in parallel.
What\'s wrong with the application note for using a higher
current pass transistor as a series regulator? App note 10.3
fig 10-5 in my copy.
How much current do you want to shunt at what voltage?
RL
12V 200W
I am thinking about either Tarlington or Qarlington.
Part Package Vbe Ib Ic Power TL431 SOT-23 0.05A 1/4W
Tarlington (3 stages) 2N2907A TO-92 5V 0.015A 0.8A 1W TIP147
TO-220 5V 0.5A 10A 125W 2N2955 TO-3 7V 7A 15A 115W
Qarlington (4 stages, 2x Darlington) MJD117 IPAK 5V 0.05A 2A 10W
MJ11011 TO-3 5V 1A 20A 200W
The application circuits, so-called, in the data sheets are just a
bunch simplified conceptual ideas you would never want to use as a
finished circuit. They have no protection for all the kinds of
things that can go wrong with the components or adverse external
events the circuit may be subjected to, especially as they cause
component failure.
The worst that can happen is that the circuit burn out as one-time fuse.
The OP is talking about using through-hole parts, so I\'m thinking this
isn\'t a production design.
Sot-23 and Ipak are SMT. SO-3 is mainly for the high power capacity.
And it doesn\'t make any sense whatsoever to use these old fashioned
linear circuits at relatively high power given the simplified thermal
management, availability and low cost of self-protecting, nearly
monolithic solutions using switching technology.
Switching isn\'t always a win even in production--it can be
difficult to keep spikes out of sensitive circuitry, for one thing. For
another, there are some applications such as moderate-accuracy
temperature control, where you can mount the pass device and heater
together. That way you get 100% driver efficiency even with a linear
control. (The drawback is that the thermal gradients tend to move
around a lot during transients, as the dissipation moves between the
heater and the pass transistor.)
For less sensitive and less specialized things, though, switching is a
win.
We have a high-performance laser driver design that includes a Class H
driver to run thermoelectrics--the switching part keeps the voltage drop
in the linear part down to below half a volt--just enough to keep the
BJT bridge out of saturation so that the active-filter action works.
Think of it as a over voltage circuit breaker/protector. When it\'s needed, efficiency is not an issue.
On Friday, August 26, 2022 at 7:49:44 AM UTC-7, Phil Hobbs wrote:
Fred Bloggs wrote:
On Thursday, August 25, 2022 at 9:08:31 PM UTC-4, Ed Lee wrote:
On Thursday, August 25, 2022 at 5:49:01 PM UTC-7, legg wrote:
On Thu, 25 Aug 2022 15:35:53 +0100, Martin Brown
\'\'\'newspam\'\'\'@nonad.co.uk> wrote:
On 25/08/2022 14:49, Ed Lee wrote:
I am looking for 3x to 5x power output of typical TL432
(100mA). Is there a higher power equivalent part? If not, i
will probably put 3 to 5 of them in parallel.
What\'s wrong with the application note for using a higher
current pass transistor as a series regulator? App note 10.3
fig 10-5 in my copy.
How much current do you want to shunt at what voltage?
RL
12V 200W
I am thinking about either Tarlington or Qarlington.
Part Package Vbe Ib Ic Power TL431 SOT-23 0.05A 1/4W
Tarlington (3 stages) 2N2907A TO-92 5V 0.015A 0.8A 1W TIP147
TO-220 5V 0.5A 10A 125W 2N2955 TO-3 7V 7A 15A 115W
Qarlington (4 stages, 2x Darlington) MJD117 IPAK 5V 0.05A 2A 10W
MJ11011 TO-3 5V 1A 20A 200W
The application circuits, so-called, in the data sheets are just a
bunch simplified conceptual ideas you would never want to use as a
finished circuit. They have no protection for all the kinds of
things that can go wrong with the components or adverse external
events the circuit may be subjected to, especially as they cause
component failure.
The worst that can happen is that the circuit burn out as one-time fuse.
The OP is talking about using through-hole parts, so I\'m thinking this
isn\'t a production design.
Sot-23 and Ipak are SMT. SO-3 is mainly for the high power capacity.
And it doesn\'t make any sense whatsoever to use these old fashioned
linear circuits at relatively high power given the simplified thermal
management, availability and low cost of self-protecting, nearly
monolithic solutions using switching technology.
Switching isn\'t always a win even in production--it can be
difficult to keep spikes out of sensitive circuitry, for one thing. For
another, there are some applications such as moderate-accuracy
temperature control, where you can mount the pass device and heater
together. That way you get 100% driver efficiency even with a linear
control. (The drawback is that the thermal gradients tend to move
around a lot during transients, as the dissipation moves between the
heater and the pass transistor.)
For less sensitive and less specialized things, though, switching is a
win.
We have a high-performance laser driver design that includes a Class H
driver to run thermoelectrics--the switching part keeps the voltage drop
in the linear part down to below half a volt--just enough to keep the
BJT bridge out of saturation so that the active-filter action works.
Think of it as a over voltage circuit breaker/protector. When it\'s needed, efficiency is not an issue.
Fred Bloggs wrote:
On Thursday, August 25, 2022 at 9:08:31 PM UTC-4, Ed Lee wrote:
On Thursday, August 25, 2022 at 5:49:01 PM UTC-7, legg wrote:
On Thu, 25 Aug 2022 15:35:53 +0100, Martin Brown
\'\'\'newspam\'\'\'@nonad.co.uk> wrote:
On 25/08/2022 14:49, Ed Lee wrote:
I am looking for 3x to 5x power output of typical TL432
(100mA). Is there a higher power equivalent part? If not, i
will probably put 3 to 5 of them in parallel.
What\'s wrong with the application note for using a higher
current pass transistor as a series regulator? App note 10.3
fig 10-5 in my copy.
How much current do you want to shunt at what voltage?
RL
12V 200W
I am thinking about either Tarlington or Qarlington.
Part Package Vbe Ib Ic Power TL431 SOT-23 0.05A 1/4W
Tarlington (3 stages) 2N2907A TO-92 5V 0.015A 0.8A 1W TIP147
TO-220 5V 0.5A 10A 125W 2N2955 TO-3 7V 7A 15A 115W
Qarlington (4 stages, 2x Darlington) MJD117 IPAK 5V 0.05A 2A 10W
MJ11011 TO-3 5V 1A 20A 200W
The application circuits, so-called, in the data sheets are just a
bunch simplified conceptual ideas you would never want to use as a
finished circuit. They have no protection for all the kinds of
things that can go wrong with the components or adverse external
events the circuit may be subjected to, especially as they cause
component failure.
The OP is talking about using through-hole parts, so I\'m thinking this
isn\'t a production design.
And it doesn\'t make any sense whatsoever to use these old fashioned
linear circuits at relatively high power given the simplified thermal
management, availability and low cost of self-protecting, nearly
monolithic solutions using switching technology.
Switching isn\'t always a win even in production--it can be
difficult to keep spikes out of sensitive circuitry, for one thing. For
another, there are some applications such as moderate-accuracy
temperature control, where you can mount the pass device and heater
together. That way you get 100% driver efficiency even with a linear
control. (The drawback is that the thermal gradients tend to move
around a lot during transients, as the dissipation moves between the
heater and the pass transistor.)
For less sensitive and less specialized things, though, switching is a
win.
We have a high-performance laser driver design that includes a Class H
driver to run thermoelectrics--the switching part keeps the voltage drop
in the linear part down to below half a volt--just enough to keep the
BJT bridge out of saturation so that the active-filter action works.
On Friday, August 26, 2022 at 11:08:48 AM UTC-4, Ed Lee wrote:
On Friday, August 26, 2022 at 7:49:44 AM UTC-7, Phil Hobbs wrote:
Fred Bloggs wrote:
On Thursday, August 25, 2022 at 9:08:31 PM UTC-4, Ed Lee wrote:
On Thursday, August 25, 2022 at 5:49:01 PM UTC-7, legg wrote:
On Thu, 25 Aug 2022 15:35:53 +0100, Martin Brown
\'\'\'newspam\'\'\'@nonad.co.uk> wrote:
On 25/08/2022 14:49, Ed Lee wrote:
I am looking for 3x to 5x power output of typical TL432
(100mA). Is there a higher power equivalent part? If not, i
will probably put 3 to 5 of them in parallel.
What\'s wrong with the application note for using a higher
current pass transistor as a series regulator? App note 10.3
fig 10-5 in my copy.
How much current do you want to shunt at what voltage?
RL
12V 200W
I am thinking about either Tarlington or Qarlington.
Part Package Vbe Ib Ic Power TL431 SOT-23 0.05A 1/4W
Tarlington (3 stages) 2N2907A TO-92 5V 0.015A 0.8A 1W TIP147
TO-220 5V 0.5A 10A 125W 2N2955 TO-3 7V 7A 15A 115W
Qarlington (4 stages, 2x Darlington) MJD117 IPAK 5V 0.05A 2A 10W
MJ11011 TO-3 5V 1A 20A 200W
The application circuits, so-called, in the data sheets are just a
bunch simplified conceptual ideas you would never want to use as a
finished circuit. They have no protection for all the kinds of
things that can go wrong with the components or adverse external
events the circuit may be subjected to, especially as they cause
component failure.
The worst that can happen is that the circuit burn out as one-time fuse..
The OP is talking about using through-hole parts, so I\'m thinking this
isn\'t a production design.
Sot-23 and Ipak are SMT. SO-3 is mainly for the high power capacity.
And it doesn\'t make any sense whatsoever to use these old fashioned
linear circuits at relatively high power given the simplified thermal
management, availability and low cost of self-protecting, nearly
monolithic solutions using switching technology.
Switching isn\'t always a win even in production--it can be
difficult to keep spikes out of sensitive circuitry, for one thing. For
another, there are some applications such as moderate-accuracy
temperature control, where you can mount the pass device and heater
together. That way you get 100% driver efficiency even with a linear
control. (The drawback is that the thermal gradients tend to move
around a lot during transients, as the dissipation moves between the
heater and the pass transistor.)
For less sensitive and less specialized things, though, switching is a
win.
We have a high-performance laser driver design that includes a Class H
driver to run thermoelectrics--the switching part keeps the voltage drop
in the linear part down to below half a volt--just enough to keep the
BJT bridge out of saturation so that the active-filter action works.
Think of it as a over voltage circuit breaker/protector. When it\'s needed, efficiency is not an issue.
Okay, well there are plenty of precision power clamp circuits in those voltage reference datasheet apps. Your dissipation should be transient. It helps a LOT if your clamp detection switch can signal a shutdown and make it happen. Dunno how you expect a Darlington to act as a clamp when it\'s only able to deliver current.
On Friday, August 26, 2022 at 9:19:35 AM UTC-7, Fred Bloggs wrote:
On Friday, August 26, 2022 at 11:08:48 AM UTC-4, Ed Lee wrote:
On Friday, August 26, 2022 at 7:49:44 AM UTC-7, Phil Hobbs wrote:
Fred Bloggs wrote:
On Thursday, August 25, 2022 at 9:08:31 PM UTC-4, Ed Lee wrote:
On Thursday, August 25, 2022 at 5:49:01 PM UTC-7, legg wrote:
On Thu, 25 Aug 2022 15:35:53 +0100, Martin Brown
\'\'\'newspam\'\'\'@nonad.co.uk> wrote:
On 25/08/2022 14:49, Ed Lee wrote:
I am looking for 3x to 5x power output of typical TL432
(100mA). Is there a higher power equivalent part? If not, i
will probably put 3 to 5 of them in parallel.
What\'s wrong with the application note for using a higher
current pass transistor as a series regulator? App note 10.3
fig 10-5 in my copy.
How much current do you want to shunt at what voltage?
RL
12V 200W
I am thinking about either Tarlington or Qarlington.
Part Package Vbe Ib Ic Power TL431 SOT-23 0.05A 1/4W
Tarlington (3 stages) 2N2907A TO-92 5V 0.015A 0.8A 1W TIP147
TO-220 5V 0.5A 10A 125W 2N2955 TO-3 7V 7A 15A 115W
Qarlington (4 stages, 2x Darlington) MJD117 IPAK 5V 0.05A 2A 10W
MJ11011 TO-3 5V 1A 20A 200W
The application circuits, so-called, in the data sheets are just a
bunch simplified conceptual ideas you would never want to use as a
finished circuit. They have no protection for all the kinds of
things that can go wrong with the components or adverse external
events the circuit may be subjected to, especially as they cause
component failure.
The worst that can happen is that the circuit burn out as one-time fuse.
The OP is talking about using through-hole parts, so I\'m thinking this
isn\'t a production design.
Sot-23 and Ipak are SMT. SO-3 is mainly for the high power capacity.
And it doesn\'t make any sense whatsoever to use these old fashioned
linear circuits at relatively high power given the simplified thermal
management, availability and low cost of self-protecting, nearly
monolithic solutions using switching technology.
Switching isn\'t always a win even in production--it can be
difficult to keep spikes out of sensitive circuitry, for one thing. For
another, there are some applications such as moderate-accuracy
temperature control, where you can mount the pass device and heater
together. That way you get 100% driver efficiency even with a linear
control. (The drawback is that the thermal gradients tend to move
around a lot during transients, as the dissipation moves between the
heater and the pass transistor.)
For less sensitive and less specialized things, though, switching is a
win.
We have a high-performance laser driver design that includes a Class H
driver to run thermoelectrics--the switching part keeps the voltage drop
in the linear part down to below half a volt--just enough to keep the
BJT bridge out of saturation so that the active-filter action works..
Think of it as a over voltage circuit breaker/protector. When it\'s needed, efficiency is not an issue.
Okay, well there are plenty of precision power clamp circuits in those voltage reference datasheet apps. Your dissipation should be transient. It helps a LOT if your clamp detection switch can signal a shutdown and make it happen. Dunno how you expect a Darlington to act as a clamp when it\'s only able to deliver current.
The 160W Power Darlington (with big heat sink, perhaps with power resistor as well) should stop the voltage from going higher. Cannot shutdown. The power source should continue to work, just not going too high in voltage.
On Friday, August 26, 2022 at 9:19:35 AM UTC-7, Fred Bloggs wrote:
On Friday, August 26, 2022 at 11:08:48 AM UTC-4, Ed Lee wrote:
On Friday, August 26, 2022 at 7:49:44 AM UTC-7, Phil Hobbs wrote:
Fred Bloggs wrote:
On Thursday, August 25, 2022 at 9:08:31 PM UTC-4, Ed Lee wrote:
On Thursday, August 25, 2022 at 5:49:01 PM UTC-7, legg wrote:
On Thu, 25 Aug 2022 15:35:53 +0100, Martin Brown
\'\'\'newspam\'\'\'@nonad.co.uk> wrote:
On 25/08/2022 14:49, Ed Lee wrote:
I am looking for 3x to 5x power output of typical TL432
(100mA). Is there a higher power equivalent part? If not, i
will probably put 3 to 5 of them in parallel.
What\'s wrong with the application note for using a higher
current pass transistor as a series regulator? App note 10.3
fig 10-5 in my copy.
How much current do you want to shunt at what voltage?
RL
12V 200W
I am thinking about either Tarlington or Qarlington.
Part Package Vbe Ib Ic Power TL431 SOT-23 0.05A 1/4W
Tarlington (3 stages) 2N2907A TO-92 5V 0.015A 0.8A 1W TIP147
TO-220 5V 0.5A 10A 125W 2N2955 TO-3 7V 7A 15A 115W
Qarlington (4 stages, 2x Darlington) MJD117 IPAK 5V 0.05A 2A 10W
MJ11011 TO-3 5V 1A 20A 200W
The application circuits, so-called, in the data sheets are just a
bunch simplified conceptual ideas you would never want to use as a
finished circuit. They have no protection for all the kinds of
things that can go wrong with the components or adverse external
events the circuit may be subjected to, especially as they cause
component failure.
The worst that can happen is that the circuit burn out as one-time fuse.
The OP is talking about using through-hole parts, so I\'m thinking this
isn\'t a production design.
Sot-23 and Ipak are SMT. SO-3 is mainly for the high power capacity.
And it doesn\'t make any sense whatsoever to use these old fashioned
linear circuits at relatively high power given the simplified thermal
management, availability and low cost of self-protecting, nearly
monolithic solutions using switching technology.
Switching isn\'t always a win even in production--it can be
difficult to keep spikes out of sensitive circuitry, for one thing. For
another, there are some applications such as moderate-accuracy
temperature control, where you can mount the pass device and heater
together. That way you get 100% driver efficiency even with a linear
control. (The drawback is that the thermal gradients tend to move
around a lot during transients, as the dissipation moves between the
heater and the pass transistor.)
For less sensitive and less specialized things, though, switching is a
win.
We have a high-performance laser driver design that includes a Class H
driver to run thermoelectrics--the switching part keeps the voltage drop
in the linear part down to below half a volt--just enough to keep the
BJT bridge out of saturation so that the active-filter action works..
Think of it as a over voltage circuit breaker/protector. When it\'s needed, efficiency is not an issue.
Okay, well there are plenty of precision power clamp circuits in those voltage reference datasheet apps. Your dissipation should be transient. It helps a LOT if your clamp detection switch can signal a shutdown and make it happen. Dunno how you expect a Darlington to act as a clamp when it\'s only able to deliver current.
The 160W Power Darlington (with big heat sink, perhaps with power resistor as well) should stop the voltage from going higher. Cannot shutdown. The power source should continue to work, just not going too high in voltage.
On Friday, August 26, 2022 at 12:27:40 PM UTC-4, Ed Lee wrote:
On Friday, August 26, 2022 at 9:19:35 AM UTC-7, Fred Bloggs wrote:
On Friday, August 26, 2022 at 11:08:48 AM UTC-4, Ed Lee wrote:
On Friday, August 26, 2022 at 7:49:44 AM UTC-7, Phil Hobbs wrote:
Fred Bloggs wrote:
On Thursday, August 25, 2022 at 9:08:31 PM UTC-4, Ed Lee wrote:
On Thursday, August 25, 2022 at 5:49:01 PM UTC-7, legg wrote:
On Thu, 25 Aug 2022 15:35:53 +0100, Martin Brown
\'\'\'newspam\'\'\'@nonad.co.uk> wrote:
On 25/08/2022 14:49, Ed Lee wrote:
I am looking for 3x to 5x power output of typical TL432
(100mA). Is there a higher power equivalent part? If not, i
will probably put 3 to 5 of them in parallel.
What\'s wrong with the application note for using a higher
current pass transistor as a series regulator? App note 10.3
fig 10-5 in my copy.
How much current do you want to shunt at what voltage?
RL
12V 200W
I am thinking about either Tarlington or Qarlington.
Part Package Vbe Ib Ic Power TL431 SOT-23 0.05A 1/4W
Tarlington (3 stages) 2N2907A TO-92 5V 0.015A 0.8A 1W TIP147
TO-220 5V 0.5A 10A 125W 2N2955 TO-3 7V 7A 15A 115W
Qarlington (4 stages, 2x Darlington) MJD117 IPAK 5V 0.05A 2A 10W
MJ11011 TO-3 5V 1A 20A 200W
The application circuits, so-called, in the data sheets are just a
bunch simplified conceptual ideas you would never want to use as a
finished circuit. They have no protection for all the kinds of
things that can go wrong with the components or adverse external
events the circuit may be subjected to, especially as they cause
component failure.
The worst that can happen is that the circuit burn out as one-time fuse.
The OP is talking about using through-hole parts, so I\'m thinking this
isn\'t a production design.
Sot-23 and Ipak are SMT. SO-3 is mainly for the high power capacity..
And it doesn\'t make any sense whatsoever to use these old fashioned
linear circuits at relatively high power given the simplified thermal
management, availability and low cost of self-protecting, nearly
monolithic solutions using switching technology.
Switching isn\'t always a win even in production--it can be
difficult to keep spikes out of sensitive circuitry, for one thing. For
another, there are some applications such as moderate-accuracy
temperature control, where you can mount the pass device and heater
together. That way you get 100% driver efficiency even with a linear
control. (The drawback is that the thermal gradients tend to move
around a lot during transients, as the dissipation moves between the
heater and the pass transistor.)
For less sensitive and less specialized things, though, switching is a
win.
We have a high-performance laser driver design that includes a Class H
driver to run thermoelectrics--the switching part keeps the voltage drop
in the linear part down to below half a volt--just enough to keep the
BJT bridge out of saturation so that the active-filter action works.
Think of it as a over voltage circuit breaker/protector. When it\'s needed, efficiency is not an issue.
Okay, well there are plenty of precision power clamp circuits in those voltage reference datasheet apps. Your dissipation should be transient. It helps a LOT if your clamp detection switch can signal a shutdown and make it happen. Dunno how you expect a Darlington to act as a clamp when it\'s only able to deliver current.
The 160W Power Darlington (with big heat sink, perhaps with power resistor as well) should stop the voltage from going higher. Cannot shutdown. The power source should continue to work, just not going too high in voltage.
And just exactly how will it do that when your external power source is back biasing its BE junctions?
fredag den 26. august 2022 kl. 18.27.40 UTC+2 skrev Ed Lee:
On Friday, August 26, 2022 at 9:19:35 AM UTC-7, Fred Bloggs wrote:
On Friday, August 26, 2022 at 11:08:48 AM UTC-4, Ed Lee wrote:
On Friday, August 26, 2022 at 7:49:44 AM UTC-7, Phil Hobbs wrote:
Fred Bloggs wrote:
On Thursday, August 25, 2022 at 9:08:31 PM UTC-4, Ed Lee wrote:
On Thursday, August 25, 2022 at 5:49:01 PM UTC-7, legg wrote:
On Thu, 25 Aug 2022 15:35:53 +0100, Martin Brown
\'\'\'newspam\'\'\'@nonad.co.uk> wrote:
On 25/08/2022 14:49, Ed Lee wrote:
I am looking for 3x to 5x power output of typical TL432
(100mA). Is there a higher power equivalent part? If not, i
will probably put 3 to 5 of them in parallel.
What\'s wrong with the application note for using a higher
current pass transistor as a series regulator? App note 10.3
fig 10-5 in my copy.
How much current do you want to shunt at what voltage?
RL
12V 200W
I am thinking about either Tarlington or Qarlington.
Part Package Vbe Ib Ic Power TL431 SOT-23 0.05A 1/4W
Tarlington (3 stages) 2N2907A TO-92 5V 0.015A 0.8A 1W TIP147
TO-220 5V 0.5A 10A 125W 2N2955 TO-3 7V 7A 15A 115W
Qarlington (4 stages, 2x Darlington) MJD117 IPAK 5V 0.05A 2A 10W
MJ11011 TO-3 5V 1A 20A 200W
The application circuits, so-called, in the data sheets are just a
bunch simplified conceptual ideas you would never want to use as a
finished circuit. They have no protection for all the kinds of
things that can go wrong with the components or adverse external
events the circuit may be subjected to, especially as they cause
component failure.
The worst that can happen is that the circuit burn out as one-time fuse.
The OP is talking about using through-hole parts, so I\'m thinking this
isn\'t a production design.
Sot-23 and Ipak are SMT. SO-3 is mainly for the high power capacity..
And it doesn\'t make any sense whatsoever to use these old fashioned
linear circuits at relatively high power given the simplified thermal
management, availability and low cost of self-protecting, nearly
monolithic solutions using switching technology.
Switching isn\'t always a win even in production--it can be
difficult to keep spikes out of sensitive circuitry, for one thing. For
another, there are some applications such as moderate-accuracy
temperature control, where you can mount the pass device and heater
together. That way you get 100% driver efficiency even with a linear
control. (The drawback is that the thermal gradients tend to move
around a lot during transients, as the dissipation moves between the
heater and the pass transistor.)
For less sensitive and less specialized things, though, switching is a
win.
We have a high-performance laser driver design that includes a Class H
driver to run thermoelectrics--the switching part keeps the voltage drop
in the linear part down to below half a volt--just enough to keep the
BJT bridge out of saturation so that the active-filter action works.
Think of it as a over voltage circuit breaker/protector. When it\'s needed, efficiency is not an issue.
Okay, well there are plenty of precision power clamp circuits in those voltage reference datasheet apps. Your dissipation should be transient. It helps a LOT if your clamp detection switch can signal a shutdown and make it happen. Dunno how you expect a Darlington to act as a clamp when it\'s only able to deliver current.
The 160W Power Darlington (with big heat sink, perhaps with power resistor as well) should stop the voltage from going higher. Cannot shutdown. The power source should continue to work, just not going too high in voltage.
how accurate? why not series regulator?
On Friday, August 26, 2022 at 10:49:44 AM UTC-4, Phil Hobbs wrote:
Fred Bloggs wrote:
On Thursday, August 25, 2022 at 9:08:31 PM UTC-4, Ed Lee wrote:
On Thursday, August 25, 2022 at 5:49:01 PM UTC-7, legg wrote:
On Thu, 25 Aug 2022 15:35:53 +0100, Martin Brown
\'\'\'newspam\'\'\'@nonad.co.uk> wrote:
On 25/08/2022 14:49, Ed Lee wrote:
I am looking for 3x to 5x power output of typical TL432
(100mA). Is there a higher power equivalent part? If not,
i will probably put 3 to 5 of them in parallel.
What\'s wrong with the application note for using a higher
current pass transistor as a series regulator? App note
10.3 fig 10-5 in my copy.
How much current do you want to shunt at what voltage?
RL
12V 200W
I am thinking about either Tarlington or Qarlington.
Part Package Vbe Ib Ic Power TL431 SOT-23 0.05A 1/4W
Tarlington (3 stages) 2N2907A TO-92 5V 0.015A 0.8A 1W TIP147
TO-220 5V 0.5A 10A 125W 2N2955 TO-3 7V 7A 15A 115W
Qarlington (4 stages, 2x Darlington) MJD117 IPAK 5V 0.05A 2A
10W MJ11011 TO-3 5V 1A 20A 200W
The application circuits, so-called, in the data sheets are just
a bunch simplified conceptual ideas you would never want to use
as a finished circuit. They have no protection for all the kinds
of things that can go wrong with the components or adverse
external events the circuit may be subjected to, especially as
they cause component failure.
The OP is talking about using through-hole parts, so I\'m thinking
this isn\'t a production design.
And it doesn\'t make any sense whatsoever to use these old
fashioned linear circuits at relatively high power given the
simplified thermal management, availability and low cost of
self-protecting, nearly monolithic solutions using switching
technology.
Switching isn\'t always a win even in production--it can be
difficult to keep spikes out of sensitive circuitry, for one thing.
For another, there are some applications such as moderate-accuracy
temperature control, where you can mount the pass device and
heater together. That way you get 100% driver efficiency even with
a linear control. (The drawback is that the thermal gradients tend
to move around a lot during transients, as the dissipation moves
between the heater and the pass transistor.)
For less sensitive and less specialized things, though, switching
is a win.
We have a high-performance laser driver design that includes a
Class H driver to run thermoelectrics--the switching part keeps the
voltage drop in the linear part down to below half a volt--just
enough to keep the BJT bridge out of saturation so that the
active-filter action works.
The problem with running bipolar with very low headroom is you lose
input ripple rejection with frequency- not completely, there is some
attenuation, but if you\'re hyper about noise then it\'s a big deal.
Like I\'m really telling you something you don\'t know...
On Friday, August 26, 2022 at 9:31:22 AM UTC-7, Fred Bloggs wrote:
On Friday, August 26, 2022 at 12:27:40 PM UTC-4, Ed Lee wrote:
On Friday, August 26, 2022 at 9:19:35 AM UTC-7, Fred Bloggs wrote:
On Friday, August 26, 2022 at 11:08:48 AM UTC-4, Ed Lee wrote:
On Friday, August 26, 2022 at 7:49:44 AM UTC-7, Phil Hobbs wrote:
Fred Bloggs wrote:
On Thursday, August 25, 2022 at 9:08:31 PM UTC-4, Ed Lee wrote:
On Thursday, August 25, 2022 at 5:49:01 PM UTC-7, legg wrote:
On Thu, 25 Aug 2022 15:35:53 +0100, Martin Brown
\'\'\'newspam\'\'\'@nonad.co.uk> wrote:
On 25/08/2022 14:49, Ed Lee wrote:
I am looking for 3x to 5x power output of typical TL432
(100mA). Is there a higher power equivalent part? If not, i
will probably put 3 to 5 of them in parallel.
What\'s wrong with the application note for using a higher
current pass transistor as a series regulator? App note 10..3
fig 10-5 in my copy.
How much current do you want to shunt at what voltage?
RL
12V 200W
I am thinking about either Tarlington or Qarlington.
Part Package Vbe Ib Ic Power TL431 SOT-23 0.05A 1/4W
Tarlington (3 stages) 2N2907A TO-92 5V 0.015A 0.8A 1W TIP147
TO-220 5V 0.5A 10A 125W 2N2955 TO-3 7V 7A 15A 115W
Qarlington (4 stages, 2x Darlington) MJD117 IPAK 5V 0.05A 2A 10W
MJ11011 TO-3 5V 1A 20A 200W
The application circuits, so-called, in the data sheets are just a
bunch simplified conceptual ideas you would never want to use as a
finished circuit. They have no protection for all the kinds of
things that can go wrong with the components or adverse external
events the circuit may be subjected to, especially as they cause
component failure.
The worst that can happen is that the circuit burn out as one-time fuse.
The OP is talking about using through-hole parts, so I\'m thinking this
isn\'t a production design.
Sot-23 and Ipak are SMT. SO-3 is mainly for the high power capacity.
And it doesn\'t make any sense whatsoever to use these old fashioned
linear circuits at relatively high power given the simplified thermal
management, availability and low cost of self-protecting, nearly
monolithic solutions using switching technology.
Switching isn\'t always a win even in production--it can be
difficult to keep spikes out of sensitive circuitry, for one thing. For
another, there are some applications such as moderate-accuracy
temperature control, where you can mount the pass device and heater
together. That way you get 100% driver efficiency even with a linear
control. (The drawback is that the thermal gradients tend to move
around a lot during transients, as the dissipation moves between the
heater and the pass transistor.)
For less sensitive and less specialized things, though, switching is a
win.
We have a high-performance laser driver design that includes a Class H
driver to run thermoelectrics--the switching part keeps the voltage drop
in the linear part down to below half a volt--just enough to keep the
BJT bridge out of saturation so that the active-filter action works.
Think of it as a over voltage circuit breaker/protector. When it\'s needed, efficiency is not an issue.
Okay, well there are plenty of precision power clamp circuits in those voltage reference datasheet apps. Your dissipation should be transient. It helps a LOT if your clamp detection switch can signal a shutdown and make it happen. Dunno how you expect a Darlington to act as a clamp when it\'s only able to deliver current.
The 160W Power Darlington (with big heat sink, perhaps with power resistor as well) should stop the voltage from going higher. Cannot shutdown. The power source should continue to work, just not going too high in voltage.
And just exactly how will it do that when your external power source is back biasing its BE junctions?
No, the TL432 is biasing PZT2907 and then 2N6287.