Synaptics Incorporated
Global coarse baseline correction charge injection

Abstract:

A global coarse baseline correction charge injection circuit comprises: an output capacitor, a slew rate control circuit, a current generator, a first current mirror, and a second current mirror. The output capacitor is configured to store a global coarse baseline correction charge. The slew rate control circuit is configured to receive a modulated voltage, a positive input current, and a negative input current as inputs, and provide a proportional-to-supply-voltage slew-rate controlled voltage as an output voltage to charge the output capacitor. The current generator is configured to receive a supply voltage as an input and provide a proportional-to-supply-voltage (PTSV) current as an output. The first current mirror is configured to mirror the PTSV current to the slew rate control circuit as the positive input current. The second current mirror is configured to mirror the PTSV current to the slew rate control circuit as the negative input current.