Constant Current Control IC for Transmission

Constant current regulation with high accuracy for inductors for automotive applications

Infineon provides a range of constant current drivers for inductive loads for various automotive applications, including but not limited to: Driving solenoids in automatic transmission, active suspension and electronic stability controls. The high accuracy regulators are capable to drive constant currents in up to eight inductors. Whereas each channel current can be programmed individually via SPI interface. On top there are sophisticated monitoring and diagnosis functions to support functional safety concepts. Pre-Drivers with external MOSFETs allow to regulate inductor currents higher than 1.5A.

Infineon´s solution for variable force or constant current controlled solenoids typically used in automatic transmissions, Idle Speed-/ valve- / suspension control or exhaust gas recirculation applications.

Highlights

What is the challenge to drive a current into inductive loads?

An inductor stores magnetic energy, which generates high negative transients when being switched off.
The challenge is to discharge the energy in a way that the switch or driver is not destroyed by the negative voltage spikes.
Infineon’s constant current drivers for inductors include a protection circuit that keeps the voltages within the
operational range.

How can I drive constant current in an inductor?

In order to achieve low power dissipation a switched regulation scheme with a constant frequency is applied.
The regulator achieve an current accuracy of 1% and below.

Where are inductive loads?

Inductors are parts of actuators as solenoids, electromechanically switches or relays. But also Motors represents inductive loads. Such solenoid actuators are being used in automatic transmission, active suspension and electronic stability controls.

How to use a constant current driver for coils?

Once programmed the inductive driver is taking care to regulate the specified current through the inductors by applying a PWM signal. So no external regulation loop is required. The constant current settings can easily be programmed via SPI interface.

When to use a Pre Driver?

At Pre driver the switching device is not integrated. The main advantage is that the power dissipation is distributed over the PCB and currents higher than 1.5A can be achieved.