TPS16630-32EVM: Peak Current and FLT/IMON Response Time during Output Short (with Design Conditions)

Tool/software:

Hi,

We are currently evaluating the TPS16630RGER in our system for output short-circuit protection.
Please find below our circuit design conditions and test results.

■ Design Conditions

• Input Voltage: +V1F = 42V

• UVLO Threshold: 28.9V

• OVP Threshold: 49.1V

• ILIM: 4.7kΩ → 3.83A

• Inrush Capacitors Total: ~909.4 μF

• MODE: Open (latched off after overcurrent)

• IMON Setting: 3.83A × 27.9 × 30kΩ ≒ 3.21V

■ Observed Behavior During Output Short Test

• Peak current of approx. 36A occurs instantly after the short, far exceeding ILIM

• IMON output responds approx. 1ms after the short

• FLT_n asserts LOW approx. 2ms after the short

■ Questions

1. Is there any way to reduce the instantaneous peak current before the fast-trip circuit activates?
   Although ILIM is set to 3.83A, nearly 36A flows momentarily during the short event.

2. Is there a way to shorten the response time from output short to changes in IMON and assertion of FLT_n?
   According to the datasheet, fast-trip delay is ~1μs, but actual IMON and FLT_n response is 1–2ms.
   We would appreciate any advice on possible ways to minimize this latency.

   

Best regards,
Conor