AN2640 datasheet(19/36 Pages) STMICROELECTRONICS

Part #	AN2640

Description	Intelligent multipower digital ballast for fluorescent lamps

PDF	36 Pages

Scroll/Zoom	100%

Manufacturer	STMICROELECTRONICS [STMicroelectronics]

Direct Link	http://www.st.com

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19 / 36 page

AN2640

L6382D5 - power management units for microcontrolled ballast

19/36

Figure 21.

Typical L6385Dx use

Another feature of the driver is the internal interlocking that avoids cross-conduction in the

half-bridge FET's. If by chance both HGI and LGI inputs are brought high at the same time,

then LSG and HSG are forced low as long as this critical condition persists.

A current sense is also available in this driver. When the voltage on pin CSI overcomes the

internal comparator reference (0.56 V, typ), the block latches the fault condition. In this state

the OCP block forces both HSD and LSD signals low while CSO is forced high so that it can

be sent to an input pin of the microcontroller that, based on its programming, starts the

proper protection sequence. The CSO output remains latched high until LSI and HSI are

simultaneously low (e.g. during dead time) and CSI is below 0.5 V. This function is suitable

to implement an overcurrent protection or hard-switching detection by using an external

AN2640 Datasheet(PDF) 19 Page - STMicroelectronics