DC/DC Converter Clamp Circuit Reducing Power and Area
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Solution Overview
Problem
Existing DC/DC converters have high power consumption and large chip area due to the clamp circuit, which is inefficient and occupies excessive space.
Innovation Solution
A DC/DC converter design incorporating an error amplifier circuit, a clamp circuit with a constant voltage and current circuit, a PWM comparator, and a ramp wave generating circuit, where the clamp circuit operates only when the error amplifier output is raised, reducing current consumption and chip area by minimizing the number of elements used.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a clamp circuit is added to the DC/DC converter, then the output voltage of the error amplifier circuit is clamped, but the current consumption and chip area increase
Solution Approach 1:
The clamp circuit is designed to operate periodically rather than continuously. The PNP bipolar transistor is activated only when the error amplifier output voltage exceeds the clamping threshold voltage VE1, and remains inactive otherwise. This periodic operation mode significantly reduces the current consumption of the clamp circuit while maintaining its voltage clamping function when needed.
2Reliability
If a clamp circuit is added to the DC/DC converter, then the output voltage of the error amplifier circuit is clamped, but the chip area increases
Solution Approach 1:
The clamp circuit is merged with the existing error amplifier circuit by sharing the PNP bipolar transistor's base connection with the error amplifier output node. This integration allows the clamp function to be added without requiring completely separate circuit components, thereby minimizing the additional chip area required while still providing effective voltage clamping.
3Reliability
If a clamp circuit with multiple transistors and circuits is used, then the clamping function is achieved, but the device complexity increases
Solution Approach 1:
The invention extracts and utilizes the existing PNP bipolar transistor from the error amplifier circuit for the clamping function, rather than adding a completely separate clamp circuit. By taking out the clamping function and implementing it through the existing transistor structure, the circuit complexity is minimized while maintaining the clamping capability.
Data Source
AI summary
To provide a DC/DC converter equipped with a clamp circuit having low power consumption, and reducible in chip area. A clamp circuit which clamps an output terminal of an error amplifier circuit equipped with an amplifier and a first transistor connected to an output terminal of the amplifier is configured to include a second transistor having a source connected to a source of the first transistor, a gate connected to a constant voltage circuit, and a drain connected to a constant current circuit, and a third transistor having a gate connected to the drain of the second transistor and a drain connected to the output of the amplifier.