Hello,
We have a problem in LM36274 debugging.
The LM36274 can work well when PWM disabled.
But the LM36274 does not work when the 75HZ PWM signal is input.
So we would like to ask how to set all the registers of LM36274 when the PWM signal below is input.
Input PWM signal waveform:
Schematic: input voltage is 5V
load infromation :VF is 21V ; ILED is 43mA(@75HZ, 10%duty)
Hi Patrick,
The PWM inupt have been enabled , it should be 0x02.as follows:
Currently The register configuration is as follows:
| Register address | Setting Value |
| 0X02 | 0x69 |
| 0X03 | 0x8B |
| 0X04 | 0x02 |
| 0X05 | 0xB7 |
| 0X06 | 0x00 |
| 0X07 | 0xFF |
| 0X08 | 0x1F |
| 0X10 | 0x06 |
| 0X11 | 0x77 |
Hi Patrick,
We verified that the PWM function of this chip is ok by signal generator.
But the LED current of this chip did not change with the input PWM signal.
The following the test waveform of this chip:
The following waveform we need:
Can this chip debug the waveform like the one shown above? The waveform of the LED current should be the same as the waveform of input PWM signal.
BR
Jay
Hi Patrick ,
The minimum frequency of input PWM signal of LP8556 is 75HZ.
Could you recommend a mode with the minimum frequency to 50HZ ?
BR
Jay
