Capacitor-Free LDO Circuit for Constant Power Consumption
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Solution Overview
Problem
Traditional LDO circuits require a large internal compensation capacitor, occupying significant chip area, and experience increased power consumption when the input voltage drops below the preset output value.
Innovation Solution
An LDO circuit with constant power consumption is designed without an internal compensation capacitor, utilizing input and output voltage division feedback modules to maintain constant power consumption through an operational amplifier module.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a large internal compensation capacitor is used in traditional LDO circuits, then the circuit stability is improved, but the chip area occupied increases significantly
Solution Approach 1:
The patent removes the internal compensation capacitor from the LDO circuit structure, extracting the problematic component that occupied significant chip area. The stability function is then achieved through alternative means (feedback mechanisms and circuit design) rather than relying on the removed capacitor.
Solution Approach 2:
The feedback modules in the patent perform multiple functions: they provide circuit stability compensation, enable constant power consumption control, and eliminate the need for separate compensation capacitors. This multi-functionality replaces what was previously achieved by dedicated compensation components.
2Area of stationary object
If the input voltage drops below the preset output value in existing capacitor-free LDO, then the power consumption increases, but the chip area is reduced
Solution Approach 1:
The patent introduces input voltage feedback and output voltage feedback modules that continuously monitor voltage levels and adjust circuit operation accordingly. This feedback mechanism enables constant power consumption control by detecting when input voltage drops and compensating through the operational amplifier and feedback network, preventing the power consumption increase seen in capacitor-free designs.
Solution Approach 2:
The circuit employs dynamic feedback adjustment where the operational amplifier continuously adapts the output based on feedback signals. This dynamic control allows the circuit to maintain constant power consumption across varying input voltage conditions, transitioning from static to adaptive operation.
Data Source
AI summary
An LDO circuit and method with constant power consumption without internal compensation capacitor, the circuit including: a power supply module, which supplies power to the LDO circuit based on a power supply and a current mirror; a bias module, which implements current bias based on a bias current and a current mirror; an output voltage divider feedback module, which feeds back the output voltage divider to the operational amplifier module based on a voltage divider resistor; an input voltage divider feedback module, which feeds back the input voltage divider to the operational amplifier module based on a voltage divider resistor; an operational amplifier module, which, based on input voltage divider feedback and output voltage divider feedback, sets the value of the offset resistor so that the output tube is always in the saturation zone, thereby achieving the purpose of keeping the circuit power consumption constant.