Boosted half-bridge...

P

Piotr Wyderski

Guest
Hi,

I needed some 10W of 200+kHz 50% bipolar square wave for driving a bunch
of magamps in one of my devices. The input voltage is 9.6V, so a full
bridge looked like an obvious choice, as the half bridge configuration
would allow for half the voltage swing. But I didn\'t like the
complexity, so I came up with the following HB with integrated
synchronous current-fed boost converter. One personality of the
transistors produces 2xV_IN at the upper drain with appreciable current
capacity, which might be used for free somewhere else in the device. The
other personality is a regular HB, but with double the swing of a
regular one. It is equivalent to a FB with half the complexity.
The essential part is captured by the attached sim, but prototypes
confirming its properties have successfully been built both using
silicon and GaN parts. I believe some of you might find it interesting.

Best regards, Piotr


Version 4
SHEET 1 1232 680
WIRE 496 -176 192 -176
WIRE 192 -80 192 -176
WIRE 496 -64 496 -176
WIRE 48 0 0 0
WIRE 144 0 128 0
WIRE 0 16 0 0
WIRE -240 112 -304 112
WIRE -128 112 -160 112
WIRE 0 112 0 96
WIRE 0 112 -48 112
WIRE 192 112 192 16
WIRE 192 112 0 112
WIRE 224 112 192 112
WIRE 336 112 304 112
WIRE 496 112 496 0
WIRE 496 112 416 112
WIRE -304 128 -304 112
WIRE 720 160 720 112
WIRE 912 160 720 160
WIRE 192 192 192 112
WIRE 720 192 720 160
WIRE 912 192 912 160
WIRE 496 208 496 112
WIRE -304 224 -304 208
WIRE 48 272 0 272
WIRE 144 272 128 272
WIRE 0 288 0 272
WIRE 192 304 192 288
WIRE 496 304 496 272
WIRE 720 304 720 272
WIRE 912 304 912 272
WIRE 0 384 0 368
FLAG 192 304 0
FLAG -304 224 0
FLAG 496 304 0
FLAG 0 384 0
FLAG 720 304 0
FLAG 912 304 0
FLAG 720 112 V_SEC
SYMBOL nmos 144 -80 R0
SYMATTR InstName M2
SYMATTR Value BSC100N03LS
SYMBOL res -144 96 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R1
SYMATTR Value 1m
SYMBOL voltage -304 112 R0
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V1
SYMATTR Value {V_IN}
SYMBOL ind -144 128 R270
WINDOW 0 32 56 VTop 2
WINDOW 3 5 56 VBottom 2
SYMATTR InstName L1
SYMATTR Value {L_BOOST}
SYMBOL cap 480 -64 R0
SYMATTR InstName C1
SYMATTR Value {C_HB}
SYMBOL cap 480 208 R0
SYMATTR InstName C2
SYMATTR Value {C_HB}
SYMBOL nmos 144 192 R0
SYMATTR InstName M1
SYMATTR Value BSC100N03LS
SYMBOL voltage 0 272 R0
WINDOW 0 -53 5 Left 2
WINDOW 3 36 227 Left 2
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V2
SYMATTR Value PULSE(0 {V_GATE_ON} 0 {T_RISE} {T_FALL} {T_ON} {T_PERIOD})
SYMBOL res 144 256 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 -55 68 VTop 2
SYMATTR InstName R2
SYMATTR Value {R_GATE}
SYMBOL voltage 0 0 R0
WINDOW 0 -41 -15 Left 2
WINDOW 3 35 457 Left 2
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V3
SYMATTR Value PULSE(0 {V_GATE_ON} {T_PERIOD/2} {T_RISE} {T_FALL} {T_ON}
{T_PERIOD})
SYMBOL res 144 -16 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 -53 67 VTop 2
SYMATTR InstName R3
SYMATTR Value {R_GATE}
SYMBOL ind 208 128 R270
WINDOW 0 34 27 VTop 2
WINDOW 3 89 69 VBottom 2
SYMATTR InstName L2
SYMATTR Value {LK_PRI}
SYMBOL ind2 320 128 R270
WINDOW 0 32 56 VTop 2
WINDOW 3 88 100 VBottom 2
SYMATTR InstName L3
SYMATTR Value {LM_PRI}
SYMATTR Type ind
SYMBOL ind2 736 176 M0
WINDOW 0 -34 44 Left 2
WINDOW 3 -124 77 Left 2
SYMATTR InstName L4
SYMATTR Value {LM_SEC}
SYMATTR Type ind
SYMBOL res 896 176 R0
SYMATTR InstName R4
SYMATTR Value 100
TEXT 240 -496 Left 2 !.param C_HB=22u
TEXT 240 -432 Left 2 !.param F_OSC=300k
TEXT 240 -400 Left 2 !.param T_PERIOD={1/F_OSC}
TEXT 240 -368 Left 2 !.param T_DEAD=50n
TEXT 240 -336 Left 2 !.param T_RISE=10n
TEXT 240 -304 Left 2 !.param T_FALL=10n
TEXT 240 -272 Left 2 !.param T_ON={T_PERIOD/2 - T_DEAD}
TEXT -10 536 Left 2 !.tran 10m
TEXT 240 -528 Left 2 !.param L_BOOST=22u
TEXT 240 -240 Left 2 !.param V_GATE_ON=10V
TEXT 240 -464 Left 2 !.param R_GATE=1
TEXT -16 456 Left 2 ;V3=
TEXT -16 496 Left 2 ;V2=
TEXT 736 -376 Left 2 !.param LK_PRI=5u
TEXT 736 -536 Left 2 !.param N_PRI=12
TEXT 736 -472 Left 2 !.param AL=5000
TEXT 736 -440 Left 2 !.param LM_PRI={N_PRI*N_PRI*AL/1e9}
TEXT 736 -408 Left 2 !.param LM_SEC={N_SEC*N_SEC*AL/1e9}
TEXT 736 -504 Left 2 !.param N_SEC=12
TEXT 528 136 Left 2 !K1 L3 L4 1
TEXT 240 -560 Left 2 !.param V_IN=9
 
On Fri, 19 Nov 2021 18:04:49 +0100, Piotr Wyderski
<bombald@protonmail.com> wrote:

Hi,

I needed some 10W of 200+kHz 50% bipolar square wave for driving a bunch
of magamps in one of my devices. The input voltage is 9.6V, so a full
bridge looked like an obvious choice, as the half bridge configuration
would allow for half the voltage swing. But I didn\'t like the
complexity, so I came up with the following HB with integrated
synchronous current-fed boost converter. One personality of the
transistors produces 2xV_IN at the upper drain with appreciable current
capacity, which might be used for free somewhere else in the device. The
other personality is a regular HB, but with double the swing of a
regular one. It is equivalent to a FB with half the complexity.
The essential part is captured by the attached sim, but prototypes
confirming its properties have successfully been built both using
silicon and GaN parts. I believe some of you might find it interesting.

Best regards, Piotr
Click to expand...

Impedance matching is what the transformer does, without
any added complexity.

RL


Version 4
SHEET 1 1232 680
WIRE 496 -176 192 -176
WIRE 192 -80 192 -176
WIRE 496 -64 496 -176
WIRE 48 0 0 0
WIRE 144 0 128 0
WIRE 0 16 0 0
WIRE -240 112 -304 112
WIRE -128 112 -160 112
WIRE 0 112 0 96
WIRE 0 112 -48 112
WIRE 192 112 192 16
WIRE 192 112 0 112
WIRE 224 112 192 112
WIRE 336 112 304 112
WIRE 496 112 496 0
WIRE 496 112 416 112
WIRE -304 128 -304 112
WIRE 720 160 720 112
WIRE 912 160 720 160
WIRE 192 192 192 112
WIRE 720 192 720 160
WIRE 912 192 912 160
WIRE 496 208 496 112
WIRE -304 224 -304 208
WIRE 48 272 0 272
WIRE 144 272 128 272
WIRE 0 288 0 272
WIRE 192 304 192 288
WIRE 496 304 496 272
WIRE 720 304 720 272
WIRE 912 304 912 272
WIRE 0 384 0 368
FLAG 192 304 0
FLAG -304 224 0
FLAG 496 304 0
FLAG 0 384 0
FLAG 720 304 0
FLAG 912 304 0
FLAG 720 112 V_SEC
SYMBOL nmos 144 -80 R0
SYMATTR InstName M2
SYMATTR Value BSC100N03LS
SYMBOL res -144 96 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R1
SYMATTR Value 1m
SYMBOL voltage -304 112 R0
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V1
SYMATTR Value {V_IN}
SYMBOL ind -144 128 R270
WINDOW 0 32 56 VTop 2
WINDOW 3 5 56 VBottom 2
SYMATTR InstName L1
SYMATTR Value {L_BOOST}
SYMBOL cap 480 -64 R0
SYMATTR InstName C1
SYMATTR Value {C_HB}
SYMBOL cap 480 208 R0
SYMATTR InstName C2
SYMATTR Value {C_HB}
SYMBOL nmos 144 192 R0
SYMATTR InstName M1
SYMATTR Value BSC100N03LS
SYMBOL voltage 0 272 R0
WINDOW 0 -53 5 Left 2
WINDOW 3 36 227 Left 2
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V2
SYMATTR Value PULSE(0 {V_GATE_ON} 0 {T_RISE} {T_FALL} {T_ON} {T_PERIOD})
SYMBOL res 144 256 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 -55 68 VTop 2
SYMATTR InstName R2
SYMATTR Value {R_GATE}
SYMBOL voltage 0 0 R0
WINDOW 0 -41 -15 Left 2
WINDOW 3 35 457 Left 2
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V3
SYMATTR Value PULSE(0 {V_GATE_ON} {T_PERIOD/2} {T_RISE} {T_FALL} {T_ON}
{T_PERIOD})
SYMBOL res 144 -16 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 -53 67 VTop 2
SYMATTR InstName R3
SYMATTR Value {R_GATE}
SYMBOL ind 208 128 R270
WINDOW 0 34 27 VTop 2
WINDOW 3 89 69 VBottom 2
SYMATTR InstName L2
SYMATTR Value {LK_PRI}
SYMBOL ind2 320 128 R270
WINDOW 0 32 56 VTop 2
WINDOW 3 88 100 VBottom 2
SYMATTR InstName L3
SYMATTR Value {LM_PRI}
SYMATTR Type ind
SYMBOL ind2 736 176 M0
WINDOW 0 -34 44 Left 2
WINDOW 3 -124 77 Left 2
SYMATTR InstName L4
SYMATTR Value {LM_SEC}
SYMATTR Type ind
SYMBOL res 896 176 R0
SYMATTR InstName R4
SYMATTR Value 100
TEXT 240 -496 Left 2 !.param C_HB=22u
TEXT 240 -432 Left 2 !.param F_OSC=300k
TEXT 240 -400 Left 2 !.param T_PERIOD={1/F_OSC}
TEXT 240 -368 Left 2 !.param T_DEAD=50n
TEXT 240 -336 Left 2 !.param T_RISE=10n
TEXT 240 -304 Left 2 !.param T_FALL=10n
TEXT 240 -272 Left 2 !.param T_ON={T_PERIOD/2 - T_DEAD}
TEXT -10 536 Left 2 !.tran 10m
TEXT 240 -528 Left 2 !.param L_BOOST=22u
TEXT 240 -240 Left 2 !.param V_GATE_ON=10V
TEXT 240 -464 Left 2 !.param R_GATE=1
TEXT -16 456 Left 2 ;V3=
TEXT -16 496 Left 2 ;V2=
TEXT 736 -376 Left 2 !.param LK_PRI=5u
TEXT 736 -536 Left 2 !.param N_PRI=12
TEXT 736 -472 Left 2 !.param AL=5000
TEXT 736 -440 Left 2 !.param LM_PRI={N_PRI*N_PRI*AL/1e9}
TEXT 736 -408 Left 2 !.param LM_SEC={N_SEC*N_SEC*AL/1e9}
TEXT 736 -504 Left 2 !.param N_SEC=12
TEXT 528 136 Left 2 !K1 L3 L4 1
TEXT 240 -560 Left 2 !.param V_IN=9
Click to expand...
 
On Fri, 19 Nov 2021 18:04:49 +0100, Piotr Wyderski
<bombald@protonmail.com> wrote:

Hi,

I needed some 10W of 200+kHz 50% bipolar square wave for driving a bunch
of magamps in one of my devices. The input voltage is 9.6V, so a full
bridge looked like an obvious choice, as the half bridge configuration
would allow for half the voltage swing. But I didn\'t like the
complexity, so I came up with the following HB with integrated
synchronous current-fed boost converter. One personality of the
transistors produces 2xV_IN at the upper drain with appreciable current
capacity, which might be used for free somewhere else in the device. The
other personality is a regular HB, but with double the swing of a
regular one. It is equivalent to a FB with half the complexity.
The essential part is captured by the attached sim, but prototypes
confirming its properties have successfully been built both using
silicon and GaN parts. I believe some of you might find it interesting.

Best regards, Piotr
Click to expand...

Impedance matching is what the transformer does, without
any added complexity.

RL


Version 4
SHEET 1 1232 680
WIRE 496 -176 192 -176
WIRE 192 -80 192 -176
WIRE 496 -64 496 -176
WIRE 48 0 0 0
WIRE 144 0 128 0
WIRE 0 16 0 0
WIRE -240 112 -304 112
WIRE -128 112 -160 112
WIRE 0 112 0 96
WIRE 0 112 -48 112
WIRE 192 112 192 16
WIRE 192 112 0 112
WIRE 224 112 192 112
WIRE 336 112 304 112
WIRE 496 112 496 0
WIRE 496 112 416 112
WIRE -304 128 -304 112
WIRE 720 160 720 112
WIRE 912 160 720 160
WIRE 192 192 192 112
WIRE 720 192 720 160
WIRE 912 192 912 160
WIRE 496 208 496 112
WIRE -304 224 -304 208
WIRE 48 272 0 272
WIRE 144 272 128 272
WIRE 0 288 0 272
WIRE 192 304 192 288
WIRE 496 304 496 272
WIRE 720 304 720 272
WIRE 912 304 912 272
WIRE 0 384 0 368
FLAG 192 304 0
FLAG -304 224 0
FLAG 496 304 0
FLAG 0 384 0
FLAG 720 304 0
FLAG 912 304 0
FLAG 720 112 V_SEC
SYMBOL nmos 144 -80 R0
SYMATTR InstName M2
SYMATTR Value BSC100N03LS
SYMBOL res -144 96 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R1
SYMATTR Value 1m
SYMBOL voltage -304 112 R0
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V1
SYMATTR Value {V_IN}
SYMBOL ind -144 128 R270
WINDOW 0 32 56 VTop 2
WINDOW 3 5 56 VBottom 2
SYMATTR InstName L1
SYMATTR Value {L_BOOST}
SYMBOL cap 480 -64 R0
SYMATTR InstName C1
SYMATTR Value {C_HB}
SYMBOL cap 480 208 R0
SYMATTR InstName C2
SYMATTR Value {C_HB}
SYMBOL nmos 144 192 R0
SYMATTR InstName M1
SYMATTR Value BSC100N03LS
SYMBOL voltage 0 272 R0
WINDOW 0 -53 5 Left 2
WINDOW 3 36 227 Left 2
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V2
SYMATTR Value PULSE(0 {V_GATE_ON} 0 {T_RISE} {T_FALL} {T_ON} {T_PERIOD})
SYMBOL res 144 256 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 -55 68 VTop 2
SYMATTR InstName R2
SYMATTR Value {R_GATE}
SYMBOL voltage 0 0 R0
WINDOW 0 -41 -15 Left 2
WINDOW 3 35 457 Left 2
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V3
SYMATTR Value PULSE(0 {V_GATE_ON} {T_PERIOD/2} {T_RISE} {T_FALL} {T_ON}
{T_PERIOD})
SYMBOL res 144 -16 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 -53 67 VTop 2
SYMATTR InstName R3
SYMATTR Value {R_GATE}
SYMBOL ind 208 128 R270
WINDOW 0 34 27 VTop 2
WINDOW 3 89 69 VBottom 2
SYMATTR InstName L2
SYMATTR Value {LK_PRI}
SYMBOL ind2 320 128 R270
WINDOW 0 32 56 VTop 2
WINDOW 3 88 100 VBottom 2
SYMATTR InstName L3
SYMATTR Value {LM_PRI}
SYMATTR Type ind
SYMBOL ind2 736 176 M0
WINDOW 0 -34 44 Left 2
WINDOW 3 -124 77 Left 2
SYMATTR InstName L4
SYMATTR Value {LM_SEC}
SYMATTR Type ind
SYMBOL res 896 176 R0
SYMATTR InstName R4
SYMATTR Value 100
TEXT 240 -496 Left 2 !.param C_HB=22u
TEXT 240 -432 Left 2 !.param F_OSC=300k
TEXT 240 -400 Left 2 !.param T_PERIOD={1/F_OSC}
TEXT 240 -368 Left 2 !.param T_DEAD=50n
TEXT 240 -336 Left 2 !.param T_RISE=10n
TEXT 240 -304 Left 2 !.param T_FALL=10n
TEXT 240 -272 Left 2 !.param T_ON={T_PERIOD/2 - T_DEAD}
TEXT -10 536 Left 2 !.tran 10m
TEXT 240 -528 Left 2 !.param L_BOOST=22u
TEXT 240 -240 Left 2 !.param V_GATE_ON=10V
TEXT 240 -464 Left 2 !.param R_GATE=1
TEXT -16 456 Left 2 ;V3=
TEXT -16 496 Left 2 ;V2=
TEXT 736 -376 Left 2 !.param LK_PRI=5u
TEXT 736 -536 Left 2 !.param N_PRI=12
TEXT 736 -472 Left 2 !.param AL=5000
TEXT 736 -440 Left 2 !.param LM_PRI={N_PRI*N_PRI*AL/1e9}
TEXT 736 -408 Left 2 !.param LM_SEC={N_SEC*N_SEC*AL/1e9}
TEXT 736 -504 Left 2 !.param N_SEC=12
TEXT 528 136 Left 2 !K1 L3 L4 1
TEXT 240 -560 Left 2 !.param V_IN=9
Click to expand...
 
On Fri, 19 Nov 2021 18:04:49 +0100, Piotr Wyderski
<bombald@protonmail.com> wrote:

Hi,

I needed some 10W of 200+kHz 50% bipolar square wave for driving a bunch
of magamps in one of my devices. The input voltage is 9.6V, so a full
bridge looked like an obvious choice, as the half bridge configuration
would allow for half the voltage swing. But I didn\'t like the
complexity, so I came up with the following HB with integrated
synchronous current-fed boost converter. One personality of the
transistors produces 2xV_IN at the upper drain with appreciable current
capacity, which might be used for free somewhere else in the device. The
other personality is a regular HB, but with double the swing of a
regular one. It is equivalent to a FB with half the complexity.
The essential part is captured by the attached sim, but prototypes
confirming its properties have successfully been built both using
silicon and GaN parts. I believe some of you might find it interesting.

Best regards, Piotr
Click to expand...

Impedance matching is what the transformer does, without
any added complexity.

RL


Version 4
SHEET 1 1232 680
WIRE 496 -176 192 -176
WIRE 192 -80 192 -176
WIRE 496 -64 496 -176
WIRE 48 0 0 0
WIRE 144 0 128 0
WIRE 0 16 0 0
WIRE -240 112 -304 112
WIRE -128 112 -160 112
WIRE 0 112 0 96
WIRE 0 112 -48 112
WIRE 192 112 192 16
WIRE 192 112 0 112
WIRE 224 112 192 112
WIRE 336 112 304 112
WIRE 496 112 496 0
WIRE 496 112 416 112
WIRE -304 128 -304 112
WIRE 720 160 720 112
WIRE 912 160 720 160
WIRE 192 192 192 112
WIRE 720 192 720 160
WIRE 912 192 912 160
WIRE 496 208 496 112
WIRE -304 224 -304 208
WIRE 48 272 0 272
WIRE 144 272 128 272
WIRE 0 288 0 272
WIRE 192 304 192 288
WIRE 496 304 496 272
WIRE 720 304 720 272
WIRE 912 304 912 272
WIRE 0 384 0 368
FLAG 192 304 0
FLAG -304 224 0
FLAG 496 304 0
FLAG 0 384 0
FLAG 720 304 0
FLAG 912 304 0
FLAG 720 112 V_SEC
SYMBOL nmos 144 -80 R0
SYMATTR InstName M2
SYMATTR Value BSC100N03LS
SYMBOL res -144 96 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R1
SYMATTR Value 1m
SYMBOL voltage -304 112 R0
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V1
SYMATTR Value {V_IN}
SYMBOL ind -144 128 R270
WINDOW 0 32 56 VTop 2
WINDOW 3 5 56 VBottom 2
SYMATTR InstName L1
SYMATTR Value {L_BOOST}
SYMBOL cap 480 -64 R0
SYMATTR InstName C1
SYMATTR Value {C_HB}
SYMBOL cap 480 208 R0
SYMATTR InstName C2
SYMATTR Value {C_HB}
SYMBOL nmos 144 192 R0
SYMATTR InstName M1
SYMATTR Value BSC100N03LS
SYMBOL voltage 0 272 R0
WINDOW 0 -53 5 Left 2
WINDOW 3 36 227 Left 2
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V2
SYMATTR Value PULSE(0 {V_GATE_ON} 0 {T_RISE} {T_FALL} {T_ON} {T_PERIOD})
SYMBOL res 144 256 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 -55 68 VTop 2
SYMATTR InstName R2
SYMATTR Value {R_GATE}
SYMBOL voltage 0 0 R0
WINDOW 0 -41 -15 Left 2
WINDOW 3 35 457 Left 2
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V3
SYMATTR Value PULSE(0 {V_GATE_ON} {T_PERIOD/2} {T_RISE} {T_FALL} {T_ON}
{T_PERIOD})
SYMBOL res 144 -16 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 -53 67 VTop 2
SYMATTR InstName R3
SYMATTR Value {R_GATE}
SYMBOL ind 208 128 R270
WINDOW 0 34 27 VTop 2
WINDOW 3 89 69 VBottom 2
SYMATTR InstName L2
SYMATTR Value {LK_PRI}
SYMBOL ind2 320 128 R270
WINDOW 0 32 56 VTop 2
WINDOW 3 88 100 VBottom 2
SYMATTR InstName L3
SYMATTR Value {LM_PRI}
SYMATTR Type ind
SYMBOL ind2 736 176 M0
WINDOW 0 -34 44 Left 2
WINDOW 3 -124 77 Left 2
SYMATTR InstName L4
SYMATTR Value {LM_SEC}
SYMATTR Type ind
SYMBOL res 896 176 R0
SYMATTR InstName R4
SYMATTR Value 100
TEXT 240 -496 Left 2 !.param C_HB=22u
TEXT 240 -432 Left 2 !.param F_OSC=300k
TEXT 240 -400 Left 2 !.param T_PERIOD={1/F_OSC}
TEXT 240 -368 Left 2 !.param T_DEAD=50n
TEXT 240 -336 Left 2 !.param T_RISE=10n
TEXT 240 -304 Left 2 !.param T_FALL=10n
TEXT 240 -272 Left 2 !.param T_ON={T_PERIOD/2 - T_DEAD}
TEXT -10 536 Left 2 !.tran 10m
TEXT 240 -528 Left 2 !.param L_BOOST=22u
TEXT 240 -240 Left 2 !.param V_GATE_ON=10V
TEXT 240 -464 Left 2 !.param R_GATE=1
TEXT -16 456 Left 2 ;V3=
TEXT -16 496 Left 2 ;V2=
TEXT 736 -376 Left 2 !.param LK_PRI=5u
TEXT 736 -536 Left 2 !.param N_PRI=12
TEXT 736 -472 Left 2 !.param AL=5000
TEXT 736 -440 Left 2 !.param LM_PRI={N_PRI*N_PRI*AL/1e9}
TEXT 736 -408 Left 2 !.param LM_SEC={N_SEC*N_SEC*AL/1e9}
TEXT 736 -504 Left 2 !.param N_SEC=12
TEXT 528 136 Left 2 !K1 L3 L4 1
TEXT 240 -560 Left 2 !.param V_IN=9
Click to expand...
 
On 19/11/2021 5:04 pm, Piotr Wyderski wrote:
Hi,

I needed some 10W of 200+kHz 50% bipolar square wave for driving a bunch
of magamps in one of my devices. The input voltage is 9.6V, so a full
bridge looked like an obvious choice, as the half bridge configuration
would allow for half the voltage swing. But I didn\'t like the
complexity, so I came up with the following HB with integrated
synchronous current-fed boost converter. One personality of the
transistors produces 2xV_IN at the upper drain with appreciable current
capacity, which might be used for free somewhere else in the device. The
other personality is a regular HB, but with double the swing of a
regular one. It is equivalent to a FB with half the complexity.
The essential part is captured by the attached sim, but prototypes
confirming its properties have successfully been built both using
silicon and GaN parts. I believe some of you might find it interesting.

    Best regards, Piotr


Version 4
SHEET 1 1232 680
WIRE 496 -176 192 -176
WIRE 192 -80 192 -176
WIRE 496 -64 496 -176
WIRE 48 0 0 0
WIRE 144 0 128 0
WIRE 0 16 0 0
WIRE -240 112 -304 112
WIRE -128 112 -160 112
WIRE 0 112 0 96
WIRE 0 112 -48 112
WIRE 192 112 192 16
WIRE 192 112 0 112
WIRE 224 112 192 112
WIRE 336 112 304 112
WIRE 496 112 496 0
WIRE 496 112 416 112
WIRE -304 128 -304 112
WIRE 720 160 720 112
WIRE 912 160 720 160
WIRE 192 192 192 112
WIRE 720 192 720 160
WIRE 912 192 912 160
WIRE 496 208 496 112
WIRE -304 224 -304 208
WIRE 48 272 0 272
WIRE 144 272 128 272
WIRE 0 288 0 272
WIRE 192 304 192 288
WIRE 496 304 496 272
WIRE 720 304 720 272
WIRE 912 304 912 272
WIRE 0 384 0 368
FLAG 192 304 0
FLAG -304 224 0
FLAG 496 304 0
FLAG 0 384 0
FLAG 720 304 0
FLAG 912 304 0
FLAG 720 112 V_SEC
SYMBOL nmos 144 -80 R0
SYMATTR InstName M2
SYMATTR Value BSC100N03LS
SYMBOL res -144 96 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R1
SYMATTR Value 1m
SYMBOL voltage -304 112 R0
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V1
SYMATTR Value {V_IN}
SYMBOL ind -144 128 R270
WINDOW 0 32 56 VTop 2
WINDOW 3 5 56 VBottom 2
SYMATTR InstName L1
SYMATTR Value {L_BOOST}
SYMBOL cap 480 -64 R0
SYMATTR InstName C1
SYMATTR Value {C_HB}
SYMBOL cap 480 208 R0
SYMATTR InstName C2
SYMATTR Value {C_HB}
SYMBOL nmos 144 192 R0
SYMATTR InstName M1
SYMATTR Value BSC100N03LS
SYMBOL voltage 0 272 R0
WINDOW 0 -53 5 Left 2
WINDOW 3 36 227 Left 2
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V2
SYMATTR Value PULSE(0 {V_GATE_ON} 0 {T_RISE} {T_FALL} {T_ON} {T_PERIOD})
SYMBOL res 144 256 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 -55 68 VTop 2
SYMATTR InstName R2
SYMATTR Value {R_GATE}
SYMBOL voltage 0 0 R0
WINDOW 0 -41 -15 Left 2
WINDOW 3 35 457 Left 2
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V3
SYMATTR Value PULSE(0 {V_GATE_ON} {T_PERIOD/2} {T_RISE} {T_FALL} {T_ON}
{T_PERIOD})
SYMBOL res 144 -16 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 -53 67 VTop 2
SYMATTR InstName R3
SYMATTR Value {R_GATE}
SYMBOL ind 208 128 R270
WINDOW 0 34 27 VTop 2
WINDOW 3 89 69 VBottom 2
SYMATTR InstName L2
SYMATTR Value {LK_PRI}
SYMBOL ind2 320 128 R270
WINDOW 0 32 56 VTop 2
WINDOW 3 88 100 VBottom 2
SYMATTR InstName L3
SYMATTR Value {LM_PRI}
SYMATTR Type ind
SYMBOL ind2 736 176 M0
WINDOW 0 -34 44 Left 2
WINDOW 3 -124 77 Left 2
SYMATTR InstName L4
SYMATTR Value {LM_SEC}
SYMATTR Type ind
SYMBOL res 896 176 R0
SYMATTR InstName R4
SYMATTR Value 100
TEXT 240 -496 Left 2 !.param C_HB=22u
TEXT 240 -432 Left 2 !.param F_OSC=300k
TEXT 240 -400 Left 2 !.param T_PERIOD={1/F_OSC}
TEXT 240 -368 Left 2 !.param T_DEAD=50n
TEXT 240 -336 Left 2 !.param T_RISE=10n
TEXT 240 -304 Left 2 !.param T_FALL=10n
TEXT 240 -272 Left 2 !.param T_ON={T_PERIOD/2 - T_DEAD}
TEXT -10 536 Left 2 !.tran 10m
TEXT 240 -528 Left 2 !.param L_BOOST=22u
TEXT 240 -240 Left 2 !.param V_GATE_ON=10V
TEXT 240 -464 Left 2 !.param R_GATE=1
TEXT -16 456 Left 2 ;V3=
TEXT -16 496 Left 2 ;V2=
TEXT 736 -376 Left 2 !.param LK_PRI=5u
TEXT 736 -536 Left 2 !.param N_PRI=12
TEXT 736 -472 Left 2 !.param AL=5000
TEXT 736 -440 Left 2 !.param LM_PRI={N_PRI*N_PRI*AL/1e9}
TEXT 736 -408 Left 2 !.param LM_SEC={N_SEC*N_SEC*AL/1e9}
TEXT 736 -504 Left 2 !.param N_SEC=12
TEXT 528 136 Left 2 !K1 L3 L4 1
TEXT 240 -560 Left 2 !.param V_IN=9
Click to expand...

Thanks Piotr, yes that is indeed interesting!

piglet
 
On Friday, November 19, 2021 at 1:05:06 PM UTC-4, Piotr Wyderski wrote:
Hi,

I needed some 10W of 200+kHz 50% bipolar square wave for driving a bunch
of magamps in one of my devices. The input voltage is 9.6V, so a full
bridge looked like an obvious choice, as the half bridge configuration
would allow for half the voltage swing. But I didn\'t like the
complexity, so I came up with the following HB with integrated
synchronous current-fed boost converter. One personality of the
transistors produces 2xV_IN at the upper drain with appreciable current
capacity, which might be used for free somewhere else in the device. The
other personality is a regular HB, but with double the swing of a
regular one. It is equivalent to a FB with half the complexity.
The essential part is captured by the attached sim, but prototypes
confirming its properties have successfully been built both using
silicon and GaN parts. I believe some of you might find it interesting.

Best regards, Piotr
Click to expand...

I didn\'t pull up the schematic, but what is special about this design that is not available in bridge driver chips? I had looked at a number for a project and found no shortage of devices available. I\'m thinking it might be the frequency range. A number of devices I considered would not work at 200 kHz. Are there none?

--

Rick C.

- Get 1,000 miles of free Supercharging
- Tesla referral code - https://ts.la/richard11209
 
Rick C wrote:

> I didn\'t pull up the schematic, but what is special about this design that is not available in bridge driver chips?

MOSFET drivers? They are designed for short current pulses and their
steady load capabilities are pretty mediocre, if specified at all. They
are good for 1-2W, e.g. IR21531 with the gate drivers used as a
full-bride power stage. Motor driver chips do have the necessary current
ratings, but are typically quite slow and often BJT-based.

This circuit has double the HB voltage swing while the complexity is
that of a HB. There is an inductor at the input, so it shares a number
of features with current-fed topologies. E.g. dI/dt is naturally limited
in the overload scenario, hence the overcurrent protection can be slow
and cheap. You also get high-capacity 2*VIN to use elsewhere for free,
as it is a synchronous boost too, depends on how you look at it. Ideal
for powering a class-D 15W audio amplifier in my application -- one
dedicated boost less. The savings are not only in the circuit itself,
but can be around it as well.

And it is interesting on its own for purely theoretical reasons; I have
never seen this topology before. It can be generalised to AHB, but I
need 50% duty cycle here.

Best regards, Piotr
 
On Monday, November 22, 2021 at 4:28:02 AM UTC-4, Piotr Wyderski wrote:
Rick C wrote:

I didn\'t pull up the schematic, but what is special about this design that is not available in bridge driver chips?
MOSFET drivers? They are designed for short current pulses and their
steady load capabilities are pretty mediocre, if specified at all. They
are good for 1-2W, e.g. IR21531 with the gate drivers used as a
full-bride power stage. Motor driver chips do have the necessary current
ratings, but are typically quite slow and often BJT-based.
Click to expand...

I think you missed my point. The driver chips can be used to drive the FETs with a minimum parts count providing high currents at a low cost.


This circuit has double the HB voltage swing while the complexity is
that of a HB. There is an inductor at the input, so it shares a number
of features with current-fed topologies. E.g. dI/dt is naturally limited
in the overload scenario, hence the overcurrent protection can be slow
and cheap. You also get high-capacity 2*VIN to use elsewhere for free,
as it is a synchronous boost too, depends on how you look at it. Ideal
for powering a class-D 15W audio amplifier in my application -- one
dedicated boost less. The savings are not only in the circuit itself,
but can be around it as well.
Click to expand...

Any number of the driver chips provide a boost output that is developed to drive the gates of N-FETs. Is that not similar to what you are talking about?


And it is interesting on its own for purely theoretical reasons; I have
never seen this topology before. It can be generalised to AHB, but I
need 50% duty cycle here.
Click to expand...

Ok, fair enough.

--

Rick C.

- Get 1,000 miles of free Supercharging
- Tesla referral code - https://ts.la/richard11209
 
On Mon, 22 Nov 2021 09:27:43 +0100, Piotr Wyderski
<bombald@protonmail.com> wrote:

Rick C wrote:

I didn\'t pull up the schematic, but what is special about this design that is not available in bridge driver chips?

MOSFET drivers? They are designed for short current pulses and their
steady load capabilities are pretty mediocre, if specified at all. They
are good for 1-2W, e.g. IR21531 with the gate drivers used as a
full-bride power stage. Motor driver chips do have the necessary current
ratings, but are typically quite slow and often BJT-based.

This circuit has double the HB voltage swing while the complexity is
that of a HB. There is an inductor at the input, so it shares a number
of features with current-fed topologies. E.g. dI/dt is naturally limited
in the overload scenario, hence the overcurrent protection can be slow
and cheap. You also get high-capacity 2*VIN to use elsewhere for free,
as it is a synchronous boost too, depends on how you look at it. Ideal
for powering a class-D 15W audio amplifier in my application -- one
dedicated boost less. The savings are not only in the circuit itself,
but can be around it as well.

And it is interesting on its own for purely theoretical reasons; I have
never seen this topology before. It can be generalised to AHB, but I
need 50% duty cycle here.

Best regards, Piotr
Click to expand...

I think it still requires the isolated HB driver, yes/no ?

You\'d get a simpler circuit by changing the turns ratio in the
transformer and using an unmodified HB.

While a 50/50 duty cycle is a fine concept, it doesn\'t just
occur naturally. Your circuit, as with a standard HB, depends
on capacitive coupling to generate volt-second balancing.

Once upon a time there might have been a justifiable reason
to artificially boost primary voltages - switch and cap
current capabilities being the primary bugbears - but
that\'s no longer justified by the parts budget, especially
at low power.

Do you need an isolated output? Using this topology to
drop the need for a transformer might be a selling point,
if not.

RL
 
On Mon, 22 Nov 2021 09:27:43 +0100, Piotr Wyderski
<bombald@protonmail.com> wrote:

Rick C wrote:

I didn\'t pull up the schematic, but what is special about this design that is not available in bridge driver chips?

MOSFET drivers? They are designed for short current pulses and their
steady load capabilities are pretty mediocre, if specified at all. They
are good for 1-2W, e.g. IR21531 with the gate drivers used as a
full-bride power stage. Motor driver chips do have the necessary current
ratings, but are typically quite slow and often BJT-based.

This circuit has double the HB voltage swing while the complexity is
that of a HB. There is an inductor at the input, so it shares a number
of features with current-fed topologies. E.g. dI/dt is naturally limited
in the overload scenario, hence the overcurrent protection can be slow
and cheap. You also get high-capacity 2*VIN to use elsewhere for free,
as it is a synchronous boost too, depends on how you look at it. Ideal
for powering a class-D 15W audio amplifier in my application -- one
dedicated boost less. The savings are not only in the circuit itself,
but can be around it as well.

And it is interesting on its own for purely theoretical reasons; I have
never seen this topology before. It can be generalised to AHB, but I
need 50% duty cycle here.

Best regards, Piotr
Click to expand...

don\'t know if this link will work unless you\'re logged into the
LTSpice forum.

https://groups.io/g/LTspice/files/Temp/HB-Boost%20Wyderski%202.zip

RL
 
legg wrote:

> I think it still requires the isolated HB driver, yes/no ?

It requires a driver, but a regular low/high side one. Like every other HB.

You\'d get a simpler circuit by changing the turns ratio in the
transformer and using an unmodified HB.
Click to expand...

Voltage swing is too low in low-V_IN scenarios, making the number of
primary winding turns a nuisance. This self-boosting capability fixes
that. I need to make several pairs of isolated +18V floating supplies
for SiC HB-s and drive a number of HF magamps. Lots of primaries to be
connected in parallel and powered from this bridge.

While a 50/50 duty cycle is a fine concept, it doesn\'t just
occur naturally.
Click to expand...

This 50/50 is for magamps.

> Your circuit, as with a standard HB, depends on capacitive coupling to generate volt-second balancing.

That is correct. This still is a HB, so all the usual rules apply.

Once upon a time there might have been a justifiable reason
to artificially boost primary voltages - switch and cap
current capabilities being the primary bugbears - but
that\'s no longer justified by the parts budget, especially
at low power.
Click to expand...

Higher voltage lowers the turns ratio and helps with leakage issues.
I^2*R losses are lower as well.

> Do you need an isolated output?

Many, with very low capacitive couplings between them.

Best regards, Piotr
 
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