TPS92518HV-Q1: Can it control (including PWM dimming) 10 Amp LEDs?

Hello Stanislav,

Trying to control 10A of LED current is certainly going to stretch the limits. In theory, since TPS92518HV-Q1 is a controller, you can size the external components for any current. However you should consider the following issues:

1. 10A current will require a large NFET with low RDSon, which will usually have a high gate charge. The gate driver of the TPS92518HV-Q1 may not be able to drive a large FET with sharp edges, resulting in a large switching loss due to the slow rise and fall times.

2. The large gate charge required to be moved will require a low switching frequency, otherwise the current required from the gate driver supply may exceed the max current capability, besides also causing more power dissipation in the VCC1 and VCC2 regulators internal to the IC

3. The DCR of the inductor will play a part in power disspation as well. To answer you question on peak current threshold - you will have to chose an external current sense resistor appropriate for the current target you want and the DAC setting you want (DAC setting corresponds to the voltage drop in the current sense you want - the higher this voltage is chosen, the more % accuracy you will get but the higher the power dissipation will be).

4. The TPS92518HV-Q1 is an synchronous controller - therefore, depending upon your duty cycle (VIN vs VLED) the low side diode will conduct the entire 10A for the off time of the NFET - and the forward voltage of the diode times 10A times (1-duty cycle) will be the power disspation in the diode. This will be high if your duty cycle is low.

5. In general due to the entire power loss mechanisms above, the thermal design will be very critical and need careful attention and experience in power design.

6. If your LEDs are on a remote board, then depending upon the length of cable connecting the buck output to the LEDs the inductance may cause ringing at the VLED pins everytime you dim the current - you will have to make sure that these ringing oscillations will not exceed abs max of the IC at the VLED pins (positive or negative).

In summary, it may be possible in theory, but I would request you to consider the above points.

Regards

Sumeet

Thanks a lot Sumeet! Very detailed and useful answer.