Band-gap Reference Circuit Using Charge Pump for Low Voltage Operation
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Solution Overview
Problem
Existing band-gap reference circuits produce inaccurate output voltages at relatively low power supply voltages.
Innovation Solution
A band-gap reference circuit incorporating a charge pump circuit that converts a low-level supply voltage into a higher regulating voltage, powering a reference circuit to generate a stable and accurate band-gap reference voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a conventional band-gap reference circuit is used with a low power supply voltage, then the circuit can operate at lower voltages, but the output voltage becomes inaccurate
Solution Approach 1:
A charge pump circuit is introduced as an intermediary component between the low power supply voltage source and the band-gap reference circuit. The charge pump converts the low supply voltage into a higher regulated voltage that is sufficient for accurate band-gap reference operation, thereby mediating the voltage level mismatch and enabling both low-voltage operation and high accuracy.
Solution Approach 2:
The charge pump circuit dynamically changes the voltage parameter by converting the low supply voltage (e.g., 1.2V) into a higher regulated voltage (e.g., 2.4V) that is appropriate for the band-gap reference circuit. This parameter transformation allows the reference circuit to operate accurately while the overall system can be powered by low voltage.
2Measurement precision
If the power supply voltage is increased to ensure accurate output voltage, then the output voltage accuracy improves, but the power consumption increases
Solution Approach 1:
The charge pump circuit operates periodically to generate the higher voltage needed by the band-gap reference circuit. By using periodic switching and energy transfer mechanisms, the charge pump can maintain the required voltage levels without continuous high power consumption, achieving a balance between accuracy and energy efficiency.
Solution Approach 2:
The system dynamically changes voltage parameters through the charge pump, which only consumes significant power during the voltage conversion process. Once the higher voltage is established, the band-gap reference circuit operates accurately without requiring continuously high power supply, thus reducing overall energy loss while maintaining output accuracy.
3Use of energy by moving object
If a charge pump circuit is added to enable low-voltage operation, then the circuit can operate at lower supply voltages, but the device complexity increases
Solution Approach 1:
The charge pump circuit is designed to perform multiple functions: voltage conversion, voltage regulation, and providing sufficient drive current to the band-gap reference circuit. By consolidating these functions into a single multi-functional block, the overall system complexity is managed more efficiently than if separate circuits were used for each function.
Solution Approach 2:
The charge pump circuit and band-gap reference circuit are integrated into a unified system where the charge pump's output is directly coupled to the reference circuit's power input. This merging of functions and close integration reduces the number of external components and interconnections, thereby managing complexity while enabling low-voltage operation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables operation at supply voltages lower than required, minimizing fluctuations and ensuring a stable and accurate band-gap reference voltage output.
Implementation Method 1
a charge pump circuit (10) powered by a supply voltage (Vpower) and thereby outputting a regulating voltage (Vreg) higher than the supply voltage (Vpower)
Data Source
AI summary
A band-gap reference circuit including a charge pump circuit and a reference circuit is disclosed. The charge pump circuit is powered by a supply voltage and thereby outputs a regulating voltage which is higher than the supply voltage and powers the reference circuit such that the reference circuit outputs a band-gap reference voltage. Powering the reference circuit with the regulating voltage that is made higher than the supply voltage by the charge pump circuit enables 1) normal operation of the band-gap reference circuit at the supply voltage that is lower than a lowest voltage required by the band-gap reference circuit; and 2) minimization (almost elimination) of fluctuations in the regulating voltage output from the charge pump circuit and hence a stable and more accurate band-gap reference voltage output from the band-gap reference circuit.