Overcurrent detection device
AssigneeTai-1 Microelectronics Corp.
InventorJy-Der David Tai
Life of this patent
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Abstract
The present invention discloses an overcurrent detection device, which uses a first NOT gate and a second NOT gate to reverse the logic states of a first digital signal and a second digital signal which are digitalized audio signals in a class D power amplifier. Next, a CMOS transistor receives the reversed digital signals and drives a load. A comparing circuit detects the current of the load and compares the current with the reversed first and second digital signals. When the current of the load is too high, the comparing circuit respectively outputs a first electrical signal and a second electrical signal to a first logic gate and a second logic gate. Then, the logic gate outputs a signal to activate a protection circuit to prevent the entire circuit be damaged or burned out.
Claims15
An overcurrent detection device for a class D power amplifier that is coupled to a load, comprising:
- a first NOT gate receiving a first digital signal from an input terminal thereof and reversing a logic state of said first digital signal;
- a second NOT gate receiving a second digital signal from an input terminal thereof and reversing a logic state of said second digital signal;
- a CMOS (Complementary Metal Oxide Semiconductor) transistor with two terminals respectively coupled to an output terminal of said first NOT gate and an output terminal of said second NOT gate, receiving reversed said first digital signal and reversed said second digital signal, and driving said load;
- a comparing circuit with one terminal coupled to said CMOS transistor and another two terminals coupled to said output terminal of said first NOT gate and said output terminal of said second NOT gate, receiving reversed said first digital signal and reversed said second digital signal from said two terminals thereof, detecting current of said load, comparing a detection result with reversed said first digital signal and reversed said second digital signal received at said two terminals thereof, and selectively outputting a first electrical signal and a second electrical signal;
- a first logic gate coupled to said comparing circuit, receiving said first digital signal and said first electrical signal, and outputting a first signal from an output terminal thereof indicating an overcurrent condition of the class D power amplifier;
- and
- a second logic gate coupled to said comparing circuit, receiving said second digital signal and said second electrical signal, and outputting a second signal from an output terminal thereof indicating an overcurrent condition of the class D power amplifier.
Dependencies are inferred from the claim text.