TPS92201A: Different dimming depth

Hi Andrii, 

Glad to help you! 

Could you please share the application details? 

• VIN
• LED number in serial
• ILED
• Inductor value

Could you please also share your EE? 

Thank you! 

Best, 

John. 

Hi John,

The test was done on TPS92201 EVM Board

• VIN - 5V
• LED number in serial - one LED (SFH 4716A)
• ILED - by default (500mA max)
• Inductor value - by default (2.2uH)
  

Best regards,

Andrii Novatskyi

Hi Andrii,

We will give you reply later.

Hi John,

In my case:
TPS92201 - 33:1
TPS92201A - 100:1

It looks that PFM mode gives deeper dimming.

Hi Andrii, 

Please help confirm the behavior assumption below. Feel free to correct me if I understand your case wrong. 

TPS92201: 

You applied a PWM signal into ADIM pin with certain dutycycle. When you give a dutycycle > 33%, the output current will be 500mA*dutycycle. When you applied dutycycle < 33%, what the output current will be in your case? Keep 500mA*33%? Or decreasing non-linearly? 

TPS92201A: 

When you applied ADIM dutycycle from 100% down to 1%, current should drop as value around 500mA*dutycycle? 

Thank you! 

Best, 

John. 

Hi John,

For TPS92201:
- If I apply PWM signal with 1% duty cycle into ADIM pin i will get 500mA / 33 = 15mA

For TPS92201A:
- If I apply PWM signal with 1% duty cycle into ADIM pin i will get 500mA / 100 = 5mA 

Best regards,
Andrii Novatskyi

Hi John,

Default IC(probably TPS92201) on the TPS92201 EVM Board has marking:

I have changed the default IC(probably TPS92201) to TPS92201A with marking:

1. Default IC has dimming depth 33:1, current range 15mA - 500mА
2. TPS92201A has dimming depth 100:1, current range 5mA - 500mA

Best regards,
Andrii Novatskyi

Hi John, 

Could you please tell me what default IC has soldered into EVM by his marking code?