Forums

PWM controllers... shopping

Started by sea moss April 10, 2020
Seems like every time I start a new power design, I waste a bunch of time looking for the ideal PWM controller.

At the end of the day I'd really like to have the simplest IC possible to handle just the PWM function, and I provide my own error amp, gate driver, and reference externally.  The ideal part would look like this: oscillator set by resistor, comparator non-inverting input, and pulse out.  Plus Vdd and ground equals 5 pins only!  Does anything like this exist?  

I've also been checking out the famous TL494, and MC34063 since I have never used them.  Does anyone here have horror stories from these parts that I can't infer from the datasheets?

Another one I discovered is MCP1632, pretty simple but not quite what I'm looking for.  Vdd=6V max for example, kind of sucks.  I do like how they use a 50uA current source as the reference pin, so you set Vref with a resistor or drive from low-impedance source, nice.
http://ww1.microchip.com/downloads/en/DeviceDoc/20005254A.pdf



On Friday, April 10, 2020 at 7:19:36 PM UTC-4, sea moss wrote:
> Seems like every time I start a new power design, I waste a bunch of time looking for the ideal PWM controller. > > At the end of the day I'd really like to have the simplest IC possible to handle just the PWM function, and I provide my own error amp, gate driver, and reference externally. The ideal part would look like this: oscillator set by resistor, comparator non-inverting input, and pulse out. Plus Vdd and ground equals 5 pins only! Does anything like this exist? > > I've also been checking out the famous TL494, and MC34063 since I have never used them. Does anyone here have horror stories from these parts that I can't infer from the datasheets? > > Another one I discovered is MCP1632, pretty simple but not quite what I'm looking for. Vdd=6V max for example, kind of sucks. I do like how they use a 50uA current source as the reference pin, so you set Vref with a resistor or drive from low-impedance source, nice. > http://ww1.microchip.com/downloads/en/DeviceDoc/20005254A.pdf
I can't get to a 5 pin device, but I bet I can do that in a 48 pin QFN using an FPGA. ICE5LP1K-SG48ITR50, under $3.00 qty 100. There's not much in the control world that can't be done primarily digitally these days. -- Rick C. - Get 1,000 miles of free Supercharging - Tesla referral code - https://ts.la/richard11209
On 4/10/2020 7:59 PM, Ricky C wrote:
> On Friday, April 10, 2020 at 7:19:36 PM UTC-4, sea moss wrote: >> Seems like every time I start a new power design, I waste a bunch of time looking for the ideal PWM controller. >> >> At the end of the day I'd really like to have the simplest IC possible to handle just the PWM function, and I provide my own error amp, gate driver, and reference externally. The ideal part would look like this: oscillator set by resistor, comparator non-inverting input, and pulse out. Plus Vdd and ground equals 5 pins only! Does anything like this exist? >> >> I've also been checking out the famous TL494, and MC34063 since I have never used them. Does anyone here have horror stories from these parts that I can't infer from the datasheets? >> >> Another one I discovered is MCP1632, pretty simple but not quite what I'm looking for. Vdd=6V max for example, kind of sucks. I do like how they use a 50uA current source as the reference pin, so you set Vref with a resistor or drive from low-impedance source, nice. >> http://ww1.microchip.com/downloads/en/DeviceDoc/20005254A.pdf > > I can't get to a 5 pin device, but I bet I can do that in a 48 pin QFN using an FPGA. ICE5LP1K-SG48ITR50, under $3.00 qty 100. > > There's not much in the control world that can't be done primarily digitally these days. >
ATTiny13A, 1k program memory, two PWM channels, 10 bit ADC, 20MHz clock. can do all sorts of stuff with that for 40 cent in 100s
On 4/10/2020 7:19 PM, sea moss wrote:
> Seems like every time I start a new power design, I waste a bunch of time looking for the ideal PWM controller. > > At the end of the day I'd really like to have the simplest IC possible to handle just the PWM function, and I provide my own error amp, gate driver, and reference externally. The ideal part would look like this: oscillator set by resistor, comparator non-inverting input, and pulse out. Plus Vdd and ground equals 5 pins only! Does anything like this exist? > > I've also been checking out the famous TL494, and MC34063 since I have never used them. Does anyone here have horror stories from these parts that I can't infer from the datasheets? > > Another one I discovered is MCP1632, pretty simple but not quite what I'm looking for. Vdd=6V max for example, kind of sucks. I do like how they use a 50uA current source as the reference pin, so you set Vref with a resistor or drive from low-impedance source, nice. > http://ww1.microchip.com/downloads/en/DeviceDoc/20005254A.pdf > > >
You can design your own if you want using something like the Silego/Dialog GreenPAK OTP mixed-signal PLC: <https://www.dialog-semiconductor.com/configurable-mixed-signal> They have a GUI system-designer it's pretty nice. Their prices are p. good they'll program the chips with your design probably like 30 cent per in quantities of thousands last I looked.
On 4/10/2020 8:16 PM, bitrex wrote:
> On 4/10/2020 7:19 PM, sea moss wrote: >> Seems like every time I start a new power design, I waste a bunch of >> time looking for the ideal PWM controller. >> >> At the end of the day I'd really like to have the simplest IC possible >> to handle just the PWM function, and I provide my own error amp, gate >> driver, and reference externally.&nbsp; The ideal part would look like >> this: oscillator set by resistor, comparator non-inverting input, and >> pulse out.&nbsp; Plus Vdd and ground equals 5 pins only!&nbsp; Does anything >> like this exist? >> >> I've also been checking out the famous TL494, and MC34063 since I have >> never used them.&nbsp; Does anyone here have horror stories from these >> parts that I can't infer from the datasheets? >> >> Another one I discovered is MCP1632, pretty simple but not quite what >> I'm looking for.&nbsp; Vdd=6V max for example, kind of sucks.&nbsp; I do like >> how they use a 50uA current source as the reference pin, so you set >> Vref with a resistor or drive from low-impedance source, nice. >> http://ww1.microchip.com/downloads/en/DeviceDoc/20005254A.pdf >> >> >> > > You can design your own if you want using something like the > Silego/Dialog GreenPAK OTP mixed-signal PLC: > > <https://www.dialog-semiconductor.com/configurable-mixed-signal> > > They have a GUI system-designer it's pretty nice. Their prices are p. > good they'll program the chips with your design probably like 30 cent > per in quantities of thousands last I looked.
Last I heard Apple is doing that for their switching controllers they want to roll their own vs. off-the-shelf integrated types from the major manufacturers.
> ATTiny13A, 1k program memory, two PWM channels, 10 bit ADC, 20MHz clock. > can do all sorts of stuff with that for 40 cent in 100s
Yeah but it seems like overkill to have C code that just performs a comparator function... plus I wonder how much jitter you would get from using that 10 bit ADC
> I can't get to a 5 pin device, but I bet I can do that in a 48 pin QFN using an FPGA. ICE5LP1K-SG48ITR50, under $3.00 qty 100.
You would need an FPGA with an ADC input. If you already had one on the board, then you could get this PWM block for free.
> You can design your own if you want using something like the > Silego/Dialog GreenPAK OTP mixed-signal PLC: > > <https://www.dialog-semiconductor.com/configurable-mixed-signal>
I have used Greenpaks, I really like them. Great for glue logic. Not sure if their analog blocks are up to this task, though. I'll have a browse at their current devices, it's been a few years.
On Friday, April 10, 2020 at 8:24:41 PM UTC-4, sea moss wrote:
> > ATTiny13A, 1k program memory, two PWM channels, 10 bit ADC, 20MHz clock. > > can do all sorts of stuff with that for 40 cent in 100s > > Yeah but it seems like overkill to have C code that just performs a comparator function... plus I wonder how much jitter you would get from using that 10 bit ADC
I don't recall learning about the engineering metric "overkill". A solution should be judged on the merits, not biases. My concern with a small MCU is the processing limitation, but if it does the job, fine. Your characterization of this as a comparator seems a bit short of the mark. Isn't this the bulk of the control algorithm? If it were just a comparator why not just use a comparator? -- Rick C. + Get 1,000 miles of free Supercharging + Tesla referral code - https://ts.la/richard11209
On Friday, April 10, 2020 at 8:25:46 PM UTC-4, sea moss wrote:
> > I can't get to a 5 pin device, but I bet I can do that in a 48 pin QFN using an FPGA. ICE5LP1K-SG48ITR50, under $3.00 qty 100. > > You would need an FPGA with an ADC input. If you already had one on the board, then you could get this PWM block for free.
Oh, how would that work? You can construct an ADC in any FPGA with differential inputs which is pretty much all of them. -- Rick C. -- Get 1,000 miles of free Supercharging -- Tesla referral code - https://ts.la/richard11209