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Forum Index : Microcontroller and PC projects : complementary PWM outputs
| Author | Message | ||||
| lizby Guru  Joined: 17/05/2016 Location: United StatesPosts: 3752 |
I'm building a proof-of-concept H-bridge inverter on a PicoMite RP2350 and need complementary PWM outputs (A high when B low and vice versa) for the high-side and low-side gate drivers. Testing shows that PWM 1, 10000, 50, 50 drives both A and B in phase — not complementary. An overlap test confirmed 45,000+ simultaneous highs out of 100,000 samples, which would be shoot-through in a real H-bridge. My workaround is a 2N3904 inverter on the B output which works fine for the prototype. But I'm curious whether there's a native MMBasic way to get true complementary outputs — perhaps via POKE to the PWM hardware registers, or a CSUB, or something in the PWM command I'm missing? PicoMite, Armmite F4, SensorKits, MMBasic Hardware, Games, etc. on FOTS |
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phil99 Guru Joined: 11/02/2018 Location: AustraliaPosts: 3210 |
There was a couple of years ago. PLAY SOUND had a MONO option that gave complimentary L & R signals for a bridge amplifier. I experimented with this on a small inverter but the 44.1kHz PWM frequency was a bit high for the MOSFETs I was using so switching losses were significantly higher than at 10kHz. Perhaps your PWM could be fed into pin 5 (CT) of a TL494 complimentary PWM driver. It can give a minimum deadtime. Edited 2026-05-18 11:29 by phil99 |
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