In some amplifier applications a “class D” amplifier architecture is used. For example, a class D amplifier may be used in battery-powered audio applications. In some such systems, a multi-level class D amplifier coupled to a boost converter, which increases a voltage from a power supply, may be used to deliver higher power to a load (e.g., a speaker). In a multi-level class-D amplifier, the pulse width modulated output may switch between three levels. The three levels may be ground, a battery voltage, and a boost voltage. Some class D amplifier circuits may include control logic to switch the bulk connections of some of the transistors in the circuit, to achieve multi-level outputs, in an attempt to avoid forward biasing bulk diodes of the transistors, which might occur otherwise in certain conditions.
USPTO Backgrounds
USPTO Backgrounds