SI9978DW(1999) 데이터 시트보기 (PDF) - Vishay Semiconductors

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SI9978DW
(Rev.:1999)

Configurable H-Bridge Driver

Vishay Semiconductors 

Si9978DW

Vishay Siliconix

Pin 8: CL/FAULTB

This is an open drain output which is active low. When the

MODE pin is at logic “1”, this pin functions as CL and

indicates that the H-bridge is in current limit. It stays low for

the duration of the current limit one-shot. With the MODE pin

at logic “0”, it serves as the FAULT output for half-bridge B to

indicate when an undervoltage or overcurrent condition is

detected. When indicating an overcurrent condition, the output

stays low for the duration of the current limit one-shot. The

FAULT output resets automatically when the condition clears.

comparators. Externally they are connected to the source(s)

of the low-side MOSFET(s) and the current sense resistor.

Pin 15: GND

The GND pin is the ground return for V+ and the ground

reference for the logic. Also, this is the ground reference input

for the current limit comparators and is connected to the

ground side of the internal 100-mV references. This pin

should be connected directly to the ground side of the current

sensing resistors.

Pin 9: FAULT/FAULTA

This is an open drain output which is switched low when an

undervoltage or overcurrent condition is detected. When

indicating an overcurrent condition, the output stays low for

the duration of the current limit one-shot. When the MODE

pin is at logic “1”, this pin is the H-bridge FAULT output. With

the MODE pin at logic “0”, it serves as the FAULT output for

half-bridge A. The FAULT output resets automatically when

the condition clears.

Pin 10: NC

No internal connection.

Pin 16: GBB and Pin 20, GBA

These pins drive the gates of the low-side power MOSFETs.

Pin 17: GTB and Pin 21, GTA

These pins drive the gates of the high-side power MOSFETs.

Pin 18: SB and Pin 22, SA

These are the source connections of the high-side power

MOSFETs, the drain of the external low-side power MOSFET,

the negative terminal of the bootstrap capacitor, and the

output for each half-bridge.

Pin 11: RA/CA

The timing resistor and capacitor for the current limit one-shot

are connected to this pin. The values of the resistor and

capacitor determine the off time set by the one-shot. The

one-shot is triggered when the current limit comparator

detects an overcurrent condition.

Pin 12: RB/CB

The timing resistor and capacitor for the current limit one-shot

are connected to this pin. The values of the resistor and

capacitor determine the off time set by the one-shot. The

one-shot is triggered when the current limit comparator

detects an overcurrent condition.

Pin 13: ILA+ and Pin 14, ILB+

These are the overcurrent sense inputs. Internally, they are

connected to the noninverting inputs of the current limit

Pin 19: CAPB and Pin 23, CAPA

These are the connections for the positive terminals of the

bootstrap capacitors CBA and CBB. A 0.01-µF capacitor can

be used for most applications.

Pin 24: V+

This is the only external power supply required for the

Si9978DW, and must be the same supply used to power the

H-bridge it is driving. The Si9978DW powers the low-voltage

logic, low-side gate driver, and bootstrap/ charge pump

circuits from self-contained voltage regulators which require

only a bootstrap capacitor on the CAP pins.

No voltage sensing circuitry monitors V+ directly; however, the

low-voltage, internally generated supply and the bootstrap

voltage (which are derived from V+) are directly protected by

undervoltage monitors.

FaxBack 408-970-5600, request 70011

www.siliconix.com

S-60752—Rev. D, 05-Apr-99

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