Patent ID: 8519678

Claim:
An electronic circuit, comprising: a first resistor and a second resistor and a capacitor connected in series circuit arrangement and configured to provide a time-varying signal; a zener diode and a third resistor connected in series circuit arrangement and configured to provide a voltage signal corresponding to a battery voltage present at an output node; first timer circuitry configured to provide clock pulses; second timer circuitry configured to provide a pulse width modulated signal by way of comparing the voltage signal to the time-varying signal, the second timer circuitry triggered by the clock pulses; a switching element configured to shunt an input node to a ground node in accordance with the pulse-width modulated signal; and a potentiometer coupled to the first timer circuitry, the first timer circuitry configured to provide the clock pulses in accordance with swings in the time-varying signal between a lesser threshold voltage and a greater threshold voltage, at least the greater threshold voltage being adjustable by way of the potentiometer.