AN3203 datasheet(16/49 Pages) STMICROELECTRONICS

Part #	AN3203

Description	This application note describes the characteristics and performance

PDF	49 Pages

Scroll/Zoom	100%

Manufacturer	STMICROELECTRONICS [STMicroelectronics]

Direct Link	http://www.st.com

Logo

16 / 49 page

Asymmetrical half bridge operation

AN3203

16/49

Doc ID 17402 Rev 2

2.2

Short-circuit protection

In case of a short-circuit at the AHB output the overload protection (OLP) is activated.

Figure 10 shows the pins involved in this function. When the short-circuit is applied, the

COMP pin saturates high. The IC detects this condition and starts charging the SS

capacitor. When the SS voltage reaches 5 V the system is shut down, when it reaches 6.4 V

the IC is latched. The PFC controller is also stopped: when the L6591 activates the

protection, the PFC_STOP signal pulls the L6563S RUN pin down to below the 0.8V

threshold. The latch is kept thanks to the auxiliary stage that remains active and provides

the VCC voltage.

In order to restart the system it is necessary to recycle the L6591 VCC voltage between the

UVLO thresholds. This can be done by removing the PS_ON signal in the auxiliary stage.

Figure 10.

Short-circuit behavior detail

Ch1: SS pin voltage (yellow)

Ch2: COMP pin voltage (blue)

Ch3: FGND pin voltage, (purple)

Ch4: L6563S RUN pin voltage (green)

AN3203 Datasheet(PDF) 16 Page - STMicroelectronics