A switching power supply controller includes a pulse width modulator circuit. The pulse width modulator circuit includes a delay circuit and a delay control circuit coupled to the delay circuit. The delay control circuit includes an amplifier circuit. The amplifier circuit includes a first input terminal, a second input terminal, and an output terminal. The first input terminal is coupled to a first voltage reference terminal. The second input terminal is coupled to the second voltage reference terminal. The output terminal is coupled to a control terminal of the delay circuit.