R

OSC

V

S

OSC

VIN

<STATUS>

1

75 mV

V

PEAK

V

HOLD

V

REF

PWM

CLK

D

1

L

S

V

S

OUT

LDO

UVLO

500 kW

EN

1 uA

REF

PWM

Control

Thermal

Shutdown

OSC

1Available only in the 14-pin package

7

DRV120

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SLVSBG3C – JUNE 2012 – REVISED JUNE 2016

Product Folder Links: DRV120

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Copyright © 2012–2016, Texas Instruments Incorporated

7 Detailed Description

7.1 Overview

The DRV120 device provides a PWM current converter for use with solenoids. The device provides a quick ramp

to a high peak current value in order to ensure opening of the valve or relay. The peak current is held for a

programmable time and then released to a lower value to maintain the open state of the valve or relay while

reducing the total current consumption. Peak current duration, peak current amount, hold current amount (in the

14-pin package), and PWM frequency can all be controlled by external components or used at default levels by

omitting these components (except peak current duration). Enable and disable of the switch is controlled by the

EN pin which has an internal pullup to VIN. The DRV120 also features a wide VIN range from 6 V to 28 V. Finally,

the 14-pin package features an open-drain pulldown path on the STATUS pin which is enabled as long as

undervoltage lockout or thermal shutdown has not triggered.

7.2 Functional Block Diagram

7.3 Feature Description

The DRV120 controls the current through the solenoid as shown in Figure 2. Activation starts when EN pin

voltage is pulled high either by an external driver or internal pullup. In the beginning of activation, DRV120 allows

the load current to ramp up to the peak value IPEAK and it regulates it at the peak value for the time, tKEEP, before

reducing it to IHOLD. The load current is regulated at the hold value as long as the EN pin is kept high. The initial

current ramp-up time depends on the inductance and resistance of the solenoid. Once EN pin is driven to GND,

DRV120 allows the solenoid current to decay to zero.