Digitally compensated hysteretic power supply with enhanced resolution

A power supply control circuit, comprising:

• an analog-to-digital converter (ADC) configured to receive a sense signal indicative of a load current, and to convert sense signal to a digital sense signal;
• a compensation module configured to compare the digital sense signal with a target signal, and to generate a digital control output having a number of bits including at least one bit that is toggled from a first state to a second state according to a toggling duty cycle;
• and
• a digital-to-analog converter (DAC) configured to receive the digital control output and to generate a corresponding analog pulse width modulation (PWM) signal that toggles from a first on-state level to a second on-state level according to the toggling duty cycle, the first and second on-state levels corresponding to two distinct on-states, respectively, of an output switch of a switching power supply.

A computer program product, stored on a non-transitory computer readable medium, including instructions that, when executed on a processor as a switching power supply control process, cause the processor to perform operations of:

• comparing a digital version of a current sense signal with a target signal, the current sense signal representative of a load current;
• generating, based on the comparison, a digital control output having a number of bits;
• providing the digital control output to a digital-to-analog converter (DAC), wherein the digital control output has more bits than a DAC resolution can accommodate, such that only most significant bits (MSBs) of the digital control output are applied to the DAC and remaining bits define a toggling duty cycle;
• and
• toggling a least significant bit of the MSBs from a first state to a second state according to the toggling duty cycle, thereby causing the DAC to generate a corresponding analog signal that toggles from a first state to a second state according to the toggling duty cycle, the first and second states corresponding to two distinct on-levels, respectively, of an output switch of a switching power supply.