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TPS61256: PWM laser on the output

Part Number: TPS61256

Hello,

I'd like to use the TPS61256 as a 5V regulator. It takes in 3.2-4.2VDC from a battery or 5DC when connected to USB. I want 5V on the output regardless of the voltage on the input. This regulator is going to drive a laser at 5V and < 15mA. I want to adjust the brightness and avoid mode hopping by modulating the output (1KHz - 10KHz) of the TPS61256 with an I/O pin on the CC2640r2 as shown in the schematic below. My question is should I attach BP to ground in this case or to the modulation signal? I don't see a frequency response curve for this device making me wonder if this device is intended to be modulated. Is this the correct device for my application?

Thanks for your help.

Patrick

  • Hi Patrick,

    yes, the BP should be grounded if the pass through function is not required.

    i'm not quite sure what do you try to achieve. but typically the output voltage of a boost can be modulated through EN pin signal.

    it is used to provide stable 5V for the system.

  • Hi Jasper,

    Thank you for your quick response. In the end I decided to use the regulator as intended and not modulate it's output. Instead I took the 5VDC output and used it to drive the laser directly. To modulate the laser I implemented a MOSFET on the low side of the laser as shown in the schematic below.

    Thanks again,

    Patrick