High-side switches, for instance n-channel enhancement-mode metal oxide semiconductor field-effect transistors (MOSFET), are broadly used due to their low on-resistance but require a charge pump for the generation of adequate control voltages. These charge pumps are required to have low power consumption but should provide high output currents—which are conflicting requirements. For instance, in automotive applications some high-side switches are turned on even when the car carrying the switches is turned off. This means that the power consumed by the high-side switches is drawn from the car battery, which has a limited capacity. Most power consumption occurs when a high-side switch is turned on because in this phase a charge pump commonly present in high-side semiconductor-switch driver circuits is active and generates from a supply voltage a voltage for controlling the high-side switches which is higher than the supply voltage. The supply voltage is provided by the car power network, including the car battery which is the only power source when the car is turned off. Therefore, it is desirable to provide improved driving circuits and methods to control these switches.
USPTO Backgrounds
USPTO Backgrounds