Delay correction for on-time generator circuitry

A circuit, comprising:

• a capacitor configured to provide a capacitor voltage responsive to an input current;
• a comparator configured to provide a comparator output signal responsive to the capacitor voltage and a reference voltage;
• a discharge switch configured to discharge the capacitor voltage responsive to the comparator output signal;
• a sample-hold circuit configured to sample a voltage across the capacitor responsive to the comparator output signal and provide a voltage signal representative of the sampled voltage;
• an amplifier configured to provide an amplifier output signal responsive to the voltage signal and the reference voltage, and
• a variable resistor configured to provide a resistance between the capacitor and a ground terminal responsive to the amplifier output signal to adjust the capacitor voltage to compensate for a turn-on delay of the comparator output signal.

An integrated circuit, comprising:

• control loop circuitry having a loop output;
• an on-time generator circuit having a trigger input coupled to the loop output, the on-time generator circuit comprising:
• a voltage-to-current converter having a converter input and a converter output, in which the converter input is coupled to an input voltage terminal;
• a comparator having first and second comparator inputs and a comparator output, in which the first comparator input is coupled to the converter output and the second comparator input is configured to receive a reference voltage;
• a discharge switch coupled between the first comparator input and a ground terminal;
• a capacitor having first and second capacitor terminals, the first capacitor terminal coupled to the first comparator input;
• and
• a delay correction circuit comprising:
• a sample-hold circuit coupled to the comparator output and the capacitor;
• an amplifier having first and second amplifier inputs and an amplifier output, in which the second amplifier input is coupled to the second comparator input;
• and
• a variable resistor having a control input coupled to the amplifier output;
• modulation logic having first and second modulation inputs and a modulation output, in which the first modulation input is coupled to the comparator output and the second modulation input is coupled to the loop output;
• and
• a drive circuit having a drive input and first and second drive outputs, in which the drive input is coupled to the modulation output.