PM8803 STMicroelectronics, PM8803 Datasheet - Page 28

• Manufacturer Part Number: PM8803
• Description: High efficiency integrated IEEE 802.3at PoE-PD interface and PWM controller type 2 PSE indicator, plus support for forward active clamp topology
• Manufacturer: STMicroelectronics

PWM controller
Figure 14. Overload (left) and short-circuit (right) behavior
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When a severe overcurrent occurs, like a short-circuit of an internal power component, and
0.7 V level is reached on CS, the gate driver is instantaneously shut down and a new soft-
start is performed after 4096 switching periods.
In case of persistent severe overcurrent, the control logic tries 4 cycles of fast hiccup before
completely shutting down the PWM controller.
To restart the device, after removing the cause of the overcurrent, VDD must be reduced
below the UVLO level.
Ch1: CTL signal, Ch2: 5Vout, Ch3: I input
Thermal protection
The PM8803 thermal protection limit is set to 160 °C on the junction temperature and is
always active. When this threshold is exceeded, the hot-swap MOSFET is opened and the
PWM controller is switched off.
When the junction temperature goes below about 130 °C, the converter will start
automatically, without recycling the input voltage.
Doc ID 018559 Rev 1
AM045104v1
PM8803