Part Number:TPS92515HV
Hello,
we're experimenting an issue with 10KHz PWM signal: if it goes to 0% we are not able to get a good output switching signal any more.
The datasheet says (www.ti.com/.../tps92515-q1.pdf, page 19):
"[...] if the PWM ON-time is shorter than the converter natural demanded ON-time, the PWM signal itself becomes the control signal for the high-side switch. The PWM pin activates a weak pulldown, as shown in Figure 25. Because the PWM pin is also UVLO (undervoltage lockout and device enable), when pulled low it is necessary to ensure the output is 100% OFF"
In our application there's a a spurious signal (that cannot be removed) on SW pin that come from the load. We observe that when the spurious signal goes over 8V with PWM duty cycle 0% something happens: we suppose that the "weak pulldown" is turned on, in this specific condition the regulator doesn't work, even if the PWM duty cycle goes to 100%.
The regulator start working normally only if we reduce the spurious signal (<8V).
Obviously during normal activity we cannot control the spurious signal.
Is this behaviour expected? How can we solve this issue?
Best Regards,
Daniele