Bandgap Voltage Generating Circuit Low Standby Current
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Solution Overview
Problem
Conventional bandgap voltage regulators consume high currents, including standby currents, which reduce the life expectancy of circuit power supplies in electronic appliances.
Innovation Solution
A bandgap voltage generating circuit and regulator design that eliminates the current I4 and omits the operational amplifier, using a first and second impedance element and transistors to generate a bandgap voltage with reduced power consumption, and a controller to switch between standby and active modes, ensuring low standby current and accurate voltage in active mode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional bandgap voltage regulator is used, then accurate voltage regulation is achieved, but high current consumption occurs
Solution Approach 1:
The patent extracts and removes the operational amplifier from the conventional bandgap voltage regulator circuit. By eliminating this high-power component, the circuit achieves significant current reduction while maintaining voltage regulation functionality through an alternative configuration using transistors Q3-Q6 and resistors R4-R6 in a feedback arrangement.
Solution Approach 2:
The patent changes the operating parameters of the bandgap circuit by modifying the feedback network configuration. Instead of using an operational amplifier with high power consumption, the invention uses a transistor-based feedback mechanism with adjusted resistor values (R4, R5, R6) to achieve the same voltage regulation function with lower current draw.
2Duration of action of stationary object
If standby current is reduced, then power supply life is extended, but voltage regulation accuracy may be compromised
Solution Approach 1:
The patent implements a dynamic control mechanism where transistor Q6 acts as a controllable switch in the feedback path. By adjusting the conductivity of Q6, the circuit can adapt its operating characteristics to maintain accurate voltage regulation across different current conditions, ensuring both low standby current and precise voltage control.
Solution Approach 2:
The patent employs a feedback mechanism using transistors Q3-Q6 and resistors R4-R6 to continuously monitor and adjust the output voltage. This feedback loop ensures that even with reduced current consumption in standby mode, the voltage regulation accuracy is maintained by dynamically adjusting the feedback signal based on the actual output voltage.
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
The solution significantly reduces standby current consumption while maintaining accurate voltage regulation, suitable for both standby and active modes, thus extending the life of circuit power supplies.
Implementation Method 1
the theory behind the bandgap voltage generating circuit is to add a voltage having a positive temperature coefficient to another voltage having a negative temperature coefficient such that a voltage not related to the temperature can be obtained
Implementation Method 2
the voltage difference VBE between the base and the emitter of the BJT can be represented by the following equation: VBE=Vbg−VT(a*InT−InK)
Implementation Method 3
the current I4 could be seen as a copy of current I3 by using a current mirror
Data Source
AI summary
A bandgap voltage generating circuit includes a circuit coupled to a first node and a second node, driving the first and the second nodes to the same voltage level. A first impedance element is coupled to the first node and a second impedance element is coupled to the second node, wherein the impedance of the second impedance element is larger than the impedance of the first impedance element. A first transistor is coupled to the first impedance element, and a second transistor is coupled to the second impedance element and the first transistor. The bandgap generating circuit generates a bandgap voltage at the second node.