PM8803 datasheet(28/34 Pages) STMICROELECTRONICS

Part #	PM8803

Description	High-efficiency, IEEE 802.3at compliant integrated PoE-PD interface and PWM controller

PDF	34 Pages

Scroll/Zoom	100%

Manufacturer	STMICROELECTRONICS [STMicroelectronics]

Direct Link	http://www.st.com

Logo

28 / 34 page

PWM controller

PM8803

28/34

Doc ID 018559 Rev 2

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.

Figure 14.

Overload (left) and short-circuit (right) behavior

Ch1: CTL signal, Ch2: 5Vout, Ch3: I input

5.6

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.

AM045104v1

PM8803 Datasheet(PDF) 28 Page - STMicroelectronics