Digital slope compensation in a current controller

摘要

Stable current control to an inductive load uses a digital driver having registers loaded with load control parameters from a microprocessor. The parameters, along with a counter responsive to clock pulses, control a pulse period and a pulse width which are used to operate an FET in series with the load to control load current. Current mode control develops a decreasing current limit voltage in each pulse period by decrementing a down counter at a rate and from an initial value commanded by the microprocessor, and converting the value to an analog current limit signal. The signal is compared to a load current feedback signal and the pulse width is truncated if the load current reaches the current limit signal.