Constant Voltage Circuit Using Inverse Temperature Compensation
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Solution Overview
Problem
Conventional constant voltage circuits face challenges in achieving low current consumption and reducing circuit scale while maintaining temperature-independent voltage generation, with fixed reference voltage values and high current consumption in series resistance circuits.
Innovation Solution
The proposed constant voltage circuit employs a temperature characteristic generating circuit and an inverse temperature characteristic generating circuit, along with a differential amplification circuit, to create a feedback loop that stabilizes output voltage, allowing for arbitrary voltage settings and reducing current consumption by eliminating the need for additional temperature-dependent circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a series circuit of resistances R51 and R52 is provided to generate a fractional voltage for temperature-independent constant voltage generation, then temperature independence is achieved, but current consumption increases significantly
Solution Approach 1:
The patent merges the reference voltage generation circuit and the fractional voltage generation circuit into a single shared current path. The constant current source supplies current to both the reference voltage circuit (generating VR5) and the resistor divider circuit (generating VM) simultaneously, eliminating the need for separate current paths. This integration reduces total current consumption while maintaining temperature independence through the differential amplification circuit that compares VR5 and VM.
2Reliability
If the circuit scale of the constant current source or reference voltage circuit is increased to achieve temperature independence, then temperature-independent voltage generation is improved, but device complexity increases
Solution Approach 1:
The patent employs a differential amplification circuit that continuously compares the reference voltage VR5 (which has inverse temperature characteristics) with the fractional voltage VM, and feeds back the difference to control the constant current source. This feedback mechanism automatically compensates for temperature variations, achieving temperature-independent constant voltage output without requiring complex circuit configurations or large-scale components.
3Use of energy by moving object
If additional circuit configuration is provided to reduce current consumption in the series resistance circuit, then current consumption is reduced, but manufacturing cost increases
Solution Approach 1:
The patent combines the reference voltage generation and fractional voltage generation into a single current path supplied by one constant current source. This eliminates the need for additional current-reduction circuits or complex power management structures, achieving low current consumption through straightforward circuit integration that is easy to manufacture with standard semiconductor processes.
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
This design enables the generation of a constant voltage independent of temperature with low current consumption and a reduced circuit scale, facilitating easier implementation and lower manufacturing costs.
Implementation Method 1
The differential amplification circuit 52 amplifies a voltage difference between the input reference voltage VR5 and the fractional voltage VM and outputs the result to the gate of the NPN transistor 53
Implementation Method 2
the NPN transistor 53 increases a current that flows from the output terminal 50 to the ground so as to decrease the constant voltage Vout
Data Source
AI summary
An inverse temperature characteristic generating circuit decreases an output voltage Vout by a voltage VGS, and supplies the resultant voltage as a voltage VA to a temperature characteristic generating circuit. The temperature characteristic generating circuit includes a differential amplification circuit that receives a terminal voltage VAP between resistances R22 and R23 and an emitter voltage VAM of a bipolar transistor T21, and outputs a control signal VC. When the terminal voltages VAP and VAM are equal to each other, an operation of a circuit is stable. The temperature characteristic of the voltage VA during the stable operation, and the temperature characteristic of the voltage VGS are inverse to each other and therefore cancel each other, so that the constant voltage Vout independent of temperature is output. In addition, the output terminal is not connected via a resistance to a ground, so that low current consumption can be easily achieved.