Voltage detection type overcurrent protection device for class-d amplifier
AssigneeC-Media Electronics Inc.
InventorsChi-Chen Cheng, Chih-Ying Huang
Life of this patent
Estimating the term…
Abstract
The present invention discloses a voltage detection type overcurrent protection device, which applies to the output stage of a CMOS Class-D audio amplifier. Generally, a Class-D audio amplifier is used to drive a high-load loudspeaker; therefore, it needs a high-current driver. When there is a short circuit in the load, the high current will burn out the driver stage. The present invention detects the output voltage to indirectly monitor whether the output current is too large. Once an overcurrent is detected, the output-stage transistor is turned off to stop high current lest the circuit be burned out.
Claims6
A voltage detection type overcurrent protection device for a Class-D amplifier, comprising:
- a clock logic module, connected to a PWM (Pulse Width Modulation) module and receiving a PWM signal;
- a CMOS (Complementary Metal Oxide Semiconductor) digital power amplifier, including a PMOS (P-channel MOS) transistor and an NMOS transistor, which are capable of driving a high load, wherein gates of said PMOS and NMOS (N-channel MOS) are respectively connected to said clock logic module;
- a first voltage comparator and a second voltage comparator, respectively connected to an output terminal of said CMOS digital power amplifier;
- a reference voltage circuit, setting two reference voltages respectively for said first voltage comparator and said second voltage comparator, wherein said reference voltages are derived from critical current values for overcurrent protection;
- a digital voltage debounce device with input terminals thereof respectively connected to output terminals of said first voltage comparator and said second voltage comparator;
- and
- an overcurrent protection module with input terminals thereof connected to said digital voltage debounce device and an output terminal thereof connected to said clock logic module.
Dependencies are inferred from the claim text.