L6731D

Pin connections and functions

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Pin n.

Name

Function

8

OCL

A resistor connected from this pin to ground sets the valley- current-limit.

The valley current is sensed through the low-side MOSFET(s). The internal

the following equation:

Connecting a capacitor from this pin to GND helps in reducing the noise

high-frequency noise related to the GND. Connect a capacitor only to a

"clean" GND.

9

OCH

A resistor connected from this pin and the high-side MOSFET(s) drain sets

the peak-current-limit. The peak current is sensed through the high-side

threshold is given by the following equation:

10

PHASE

This pin is connected to the source of the high-side MOSFET(s) and

provides the return path for the high-side driver. This pin monitors the drop

across both the upper and lower MOSFET(s) for the current limit together

with OCH and OCL.

11

HGATE

This pin is connected to the high-side MOSFET(s) gate.

12

BOOT

Through this pin is supplied the high-side driver. Connect a capacitor from

versus BOOT).

13

PGND

This pin has to be connected closely to the low-side MOSFET(s) source in

order to reduce the noise injection into the device.

14

LGATE

This pin is connected to the low-side MOSFET(s) gate.

15

5 V internally regulated voltage. It is used to supply the internal drivers.

Filter it to ground with at least 1 µF ceramic cap.

16

Supply voltage pin.

The operative supply voltage range is from 4.5 V to 14 V.

Table 4.

Pin functions (continued)

I

VALLEY

I

OCL

R

OCL

•

2R

DSONLS

•

----------------------------------

=

I

PEAK

I

OCH

R

OCH

•

R

DSONHS

----------------------------------

=