Bandgap Reference Feedback Circuit for Base Current Compensation
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Solution Overview
Problem
Conventional bandgap reference voltage generators face issues with power supply rejection ratio degradation, high power consumption, and increased size and manufacturing cost due to significant base currents in bipolar transistors, necessitating current compensation circuits.
Innovation Solution
The proposed bandgap reference voltage generator employs a bandgap core circuit with feedback circuitry that includes a current replica circuit and resistors to generate control voltages, eliminating the need for additional circuits by using exclusively the feedback circuitry to produce bandgap reference voltages greater or less than the threshold value, thereby reducing base currents and simplifying the design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If additional circuits (resistors, bipolar transistors, current summing circuits) are utilized to generate bandgap reference voltages at different voltage levels, then the bandgap reference voltage generator can operate at various operating voltages, but significant base current is generated in the bipolar transistors of the bandgap core circuit
Solution Approach 1:
The patent introduces a current replica circuit as an intermediary between the feedback circuitry and the bandgap core circuit. This current replica circuit replicates the feedback current and provides it to the bandgap core circuit, thereby eliminating the need for additional current summing circuits and reducing base current generation while maintaining multi-voltage level operation capability
2Reliability
If current compensation circuits are implemented to compensate for base currents, then the base current issue is addressed, but the power supply rejection ratio degrades and power consumption increases
Solution Approach 1:
The patent extracts the current compensation function from separate compensation circuits and integrates it into the feedback circuitry itself. The feedback circuitry is configured to provide feedback current that automatically compensates for base currents, eliminating the need for additional power-consuming compensation circuits while maintaining reliable base current compensation
3Reliability
If current compensation circuits are implemented to compensate for base currents, then the base current issue is addressed, but the size and manufacturing cost of the bandgap reference voltage generator increase
Solution Approach 1:
The patent merges the current compensation function with the feedback circuitry by configuring the feedback circuitry to provide feedback current that automatically compensates for base currents. This integration eliminates the need for separate compensation circuits, thereby reducing device complexity and manufacturing cost while maintaining reliable base current compensation
Data Source
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AI summary
A bandgap reference voltage generator can include a bandgap core circuit configured to output at least one control voltage. The bandgap reference voltage generator can further include feedback circuitry that can be configured to receive a control voltage outputted by the bandgap core circuit or another control voltage generated based on the control voltage, and output a current. The current can be outputted such that the current is sourced to or sank from the bandgap core circuit. The feedback circuitry can be further configured to generate a bandgap reference voltage. When the current is sourced to the bandgap core circuit, the bandgap reference voltage can be greater than a threshold value. Similarly, when the current is sank from the bandgap core circuit, the bandgap reference voltage can be less than the threshold value.