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Hello, TI guys.
I am trying to design an IR LED driver circuit as below image.
Could you review and give me a feedback?
The condition is :
- Vin : 5V
- Ouput Current : 1A
- IR LED Vf : 2V
- PWM IO level : 1.8V
Q1.
The LED parallel structure is good to apply?
Q2. How about the inductor value?
Could you recommend any specific model?
Q3.
And also, I am worried about PWM IO level is OK with it.
The IO level from host IC side is fixed in 1.8V.
Should I use level translator to change IO level to 3.3V unless 1.8V is enough?
I use level translator(TXS0108E-Q1) for other circuit part and it have some spare pins.
Q4.
For PWM input, the right model is TPS92200D (1? or 2?) DDCR?
Regards
Hi HOGYUN,
Sorry for the delay.
First of all, I would recommend you use TPS92201, our newer product, which better fits your application range.
A1. If high illumination consistency between LEDs is needed, then paralleling two strings of LEDs may not be a good choice. Considering using two LED drivers or using LEDs with small tolerance.
A2. You can choose an even smaller inductor value like 3.3uH if a larger K_IND is chosen (Please refer to Section 8.2.1.2 Detailed Design Procedure from the datasheet). Sorry but I cannot recommend any specific inductor part number for you.
A3. Please check your host IC's spec and see if it is compatible with TPS92200's spec (A screenshot of the datasheet is shown below).
A4. Both D1 and D2 version can accept PWM input.
Best Regards,
Steven
