Hello,
I made an PWM circuit using LTC6992. I used the schematic and resistors as per datasheet (the same as bellow with added capacitor). After I started troubleshooting I also checked my resistor values according to this online calculator and they mach. I have the same values for R1, R2 and used an 250 k trimmer for Rset in order to gain some frequency adjustment. Bellow you can see the screenshot from the calculator with the desired frequency of 4 kHz.
Basically I made a 0-10 V to PWM converter so in order to convert the voltage to 0-1 V range I made and adjustable voltage divider.
I have a problem with an error of the output duty cycle. I measured the following values:
As can be seen in the datasheet the error should be lower than 3,7 % and clearly it is not.
I wonder why is that happening I tried replacing the IC and also disconnect the output from the other circuitry and nothing changed. The voltage on the MOD pin is dead on, so the issue is not in the divider. Otherwise the output waveform looks superb and stable.
Thank you very much for help in advance.
I made an PWM circuit using LTC6992. I used the schematic and resistors as per datasheet (the same as bellow with added capacitor). After I started troubleshooting I also checked my resistor values according to this online calculator and they mach. I have the same values for R1, R2 and used an 250 k trimmer for Rset in order to gain some frequency adjustment. Bellow you can see the screenshot from the calculator with the desired frequency of 4 kHz.
Basically I made a 0-10 V to PWM converter so in order to convert the voltage to 0-1 V range I made and adjustable voltage divider.
I have a problem with an error of the output duty cycle. I measured the following values:
- 2 V ~14 % duty cycle,
- 5 V 50 % duty cycle, so dead on,
- 8 V ~86 % duty cycle.
As can be seen in the datasheet the error should be lower than 3,7 % and clearly it is not.
I wonder why is that happening I tried replacing the IC and also disconnect the output from the other circuitry and nothing changed. The voltage on the MOD pin is dead on, so the issue is not in the divider. Otherwise the output waveform looks superb and stable.
Thank you very much for help in advance.
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