5 ms·

What does the logic implemented using standard cell circuitry do in this design? I thought this is a "dumb" component, no calculations inside?

kayson 6y ago
Nothing as fancy as calculations. If you look at the datasheet, there is an Enable pin as well as a clock input and open drain debug output. There's also an internal oscillator. The standard cells are probably used for those features, and possibly additional internal features used for testing.
stephen_g 6y ago
It’s a switching regulator, so it’s generating PWM and adjusting duty cycles based on voltage feedback to produce a certain voltage on the output. Part of that means controlling the mosfet gates in the H-bridge. Some of that kind of thing can just be done in analogue circuits but often these kind of power supplies also can do things like hiccup modes for overcurrent, different waveforms for low load current, etc. so it could have a little state machine in it.
kens 6y ago
My guess is it's a mixture of analog and digital stuff. On the analog side, there's probably a bandgap voltage reference, temperature and current sensing, soft-start circuitry. It needs to detect the primary's clock and lock on it (probably with a PLL), and adjust the phase as necessary. Then there will be drivers for the power transistors. The digital side is probably fairly simple logic to stop the chip if there's a fault and restart it if the fault goes away. From the datasheet, there are various different overload states it can go into, limiting power, changing to passive rectification, and then shutting down entirely. So the logic would need to manage these states. There's always the possibility that they threw a microcontroller in to handle this, but it seems like overkill. Also, I didn't see anything that looked like ROM. So I think the control is hard-wired.

5 ms·

What does the logic implemented using standard cell circuitry do in this design? I thought this is a "dumb" component, no calculations inside?

by wolf550e 6y ago

kayson 6y ago
Nothing as fancy as calculations. If you look at the datasheet, there is an Enable pin as well as a clock input and open drain debug output. There's also an internal oscillator. The standard cells are probably used for those features, and possibly additional internal features used for testing.
stephen_g 6y ago
It’s a switching regulator, so it’s generating PWM and adjusting duty cycles based on voltage feedback to produce a certain voltage on the output. Part of that means controlling the mosfet gates in the H-bridge. Some of that kind of thing can just be done in analogue circuits but often these kind of power supplies also can do things like hiccup modes for overcurrent, different waveforms for low load current, etc. so it could have a little state machine in it.
kens 6y ago
My guess is it's a mixture of analog and digital stuff. On the analog side, there's probably a bandgap voltage reference, temperature and current sensing, soft-start circuitry. It needs to detect the primary's clock and lock on it (probably with a PLL), and adjust the phase as necessary. Then there will be drivers for the power transistors. The digital side is probably fairly simple logic to stop the chip if there's a fault and restart it if the fault goes away. From the datasheet, there are various different overload states it can go into, limiting power, changing to passive rectification, and then shutting down entirely. So the logic would need to manage these states. There's always the possibility that they threw a microcontroller in to handle this, but it seems like overkill. Also, I didn't see anything that looked like ROM. So I think the control is hard-wired.