Dual, Redundant, H-Bridge Motor Driver with ASIL Diagnostics

The MAX20082 is a dual, full-bridge controller specifically designed for fault-tolerant automotive applications with high-power inductive loads such as brushed DC motors. The device has two fully independent motor-control channels designed for use with external n-channel power MOSFETs. Each channel operates from a 4.75V to 5.25V input supply voltage range, and is capable of working with motor supply voltages up to 35V.

A charge-pump regulator provides 9.8V gate drive with a 5V input supply voltage. A bootstrap capacitor is used to provide the voltage above the input battery voltage necessary to drive the high-side n-channel MOSFETs in the H-bridge. An internal top-off charge pump for the high-side drive allows DC (100% duty cycle) operation.

The device also includes programmable dead time, gate-drive slew rate, and MOSFET short-circuit threshold. The H-bridge can be driven in forward mode (clockwise), reverse mode (counterclockwise), braking mode, and coast mode. In braking mode, both the low-side MOSFETs are turned on (synchronous slow decay). In coast mode, all the MOSFETs in the H-bridge are off (asynchronous fast decay). The power MOSFETs are protected from shoot-through by a resistor-adjustable dead-time circuit.

Each channel also integrates a low-side current-sense amplifier. Used for sensing motor (H-bridge) current, the current-sense amplifier includes an overcurrent-protection circuit to limit the current in the event of motor faults.

Integrated diagnostics provide indication of undervoltage, overtemperature, H-bridge, and pin faults and can be configured to protect the power MOSFETs under most short-circuit conditions. In addition, the device supports implementation in ASIL systems by having two completely redundant H-bridge drivers in one package. The two channels are completely independent and fully redundant, with no shared pins or functions.

The MAX20082 is specified for operation over the full -40°C to +125°C ambient temperature range. The maximum junction temperature is 150°C, with thermal shutdown at 170°C (typ). The device is available in a 56-pin, 14mm × 6.1mm, TSSOP package.

Applications

* Automotive Motor Drivers * Industrial Motor Drivers

* Comprehensive IC Diagnostics Detect Both IC and H-Bridge Faults, Enhancing System Safety

* Both Channels are Fully Independent Without Any Shared Pins or Circuitry, Providing Complete Redundancy

* Resistor-Programmable Functionality Simplifies Software Development

* All nFET Operation, Including 100% Duty Cycle, Saves System Cost