1 Features

• AEC-Q100 qualified for automotive applications

– Temperature grade 1: –40°C to +125°C, TA

• Functional Safety-Compliant targeted

– Developed for functional safety applications

– Documentation to aid ISO26262 system design

up to ASIL C will be available

• Highly integrated solenoid driver targeted at

automotive EV contactor relay and solenoid control

applications

– Integration of power supplies, current

regulation, diagnostics, and safety functions

– High-efficiency solenoid driving with

configurable peak and hold current settings

– Built-in-self-test and diagnostic functions for

power supplies, interfaces, drivers, and

monitors

– Architecture for reliable operation with

redundant power supplies, low-side and highside

drivers, and secondary monitoring logic

• Up to 28-V (40-V abs. max) operating voltage

• Integrated modified half-bridge

– For charging, recirculation and clamping

– Typical RDS(ON): 37 mΩ (low-side), 57 mΩ

(high-side)

– Quick Turn Off with integrated clamp circuits

– High-side clamp with redundant low-side clamp

• Low-side load control by single wire connection

– Allows external high-side switch for redundant

shut-off

• ± 5 accurate Low and High-side current sense

– Analog load current feedback pin (IPROPI)

• Internal control mode:

– Closed loop PWM current regulation

– Configurable peak time, peak and hold currents

• External control mode:

– Vary duty cycle at fixed PWM frequency

– Vary PWM frequency at fixed duty cycle

• 4-wire, addressable, 24-bit SPI with CRC

– Allows multiple devices to operate on same SPI

– Can broadcast commands to multiple devices

• Comprehensive protection and diagnostics:

– Device built-in-self-test

– Load monitoring for open/short detection

– Sensing loss of control during driver ON and

OFF

– Forced relay open for undercurrent or

undervoltage

– Redundant pin shut-off

– Fault notification on nFAULT pin

2 Applications

• EV Contactor relays

• Peak and hold solenoids

• On and off relays

• Proportional solenoids

• Battery Disconnect Units (BDUs)

• Battery Junction Boxes (BJBs)

• Power Distribution Boxes (PDBs)

• Active Suspension Systems

• Vehicle Control Units (VCUs)

3 Description

The DRV3946-Q1 is a highly integrated solution to drive two solenoids for automotive applications such

as contactor relays in EV battery management systems. It includes power supplies, current sensing and

current regulation, configurable peak and hold currents and associated timings, and diagnostics and protection

functions. It also incorporates several unique functions that enhance performance compared to traditional

discrete solenoid drivers. These functions include integrated redundant clamp circuits to quickly discharge the

load current, an addressable SPI, and modified half-bridge driver stage with low on-resistance switches.

The device controls solenoid loads through a single wire low-side connection and can pair with an external

high-side switch (that can be shared) for redundant shut-off function. Integrated switches perform charging,

recirculation and clamping. The device supports internal and external current control modes. The PWM

frequency is configurable, with added low frequency dithering using automatic pseudo random frequencies

generation and wave shaping. Internal PWM current control loop leads to reduced software development, since

MCU current control loop is not needed. The DRV3946-Q1 supports flexible current control parameters to

support wide range of solenoid types. Configurable peak and hold current and corresponding timing parameters

allow system level power saving.

The DRV3946-Q1 is targeted to be functional safety-compliant, with ASIL-C rated functional safety goal for

relay control and avoiding unintended operation. The device supports comprehensive protection and diagnostic

features, such as continuous monitoring of load for open and short detection, on and off-state diagnostics,

voltage monitors, short protection and high voltage rated IOs.

An addressable SPI allows multiple devices to be controlled on a shared SPI bus. In addition to reducing

required MCU resources, the addressable SPI incorporates a broadcast command structure that can enable

all devices on the shared addressed bus to take certain actions simultaneously. The SPI incorporates multiple

robustness functions including a CRC, address readback capability, and various bus fault detection mechanisms.