Bandgap Voltage Reference Circuit with High PSRR
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing bandgap voltage reference circuits suffer from low power supply rejection ratio, high power consumption, large chip-area requirements, and increased complexity due to cascode configurations and the need for voltage buffers, which also introduce temperature-dependent offset errors.
Innovation Solution
A low power bandgap voltage reference circuit with a high power supply rejection ratio is achieved using a voltage regulator, a bandgap voltage circuit, and an amplifier, where the bandgap voltage circuit employs a current mirror and resistors to generate a voltage difference between transistors, and an amplifier regulates the voltage source, allowing for multiple reference voltages without a buffer, thereby reducing chip area and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cascode circuits are used to increase power supply rejection ratio, then PSRR is improved, but voltage headroom is reduced and chip area increases
Solution Approach 1:
The patent combines the voltage regulation function and bandgap reference function into a single integrated circuit block. The regulator circuit directly controls the bandgap reference circuit without requiring separate cascode stages, merging multiple functions into one compact unit that achieves high PSRR without proportionally increasing chip area.
Solution Approach 2:
The regulator circuit serves multiple functions simultaneously: it provides voltage regulation, generates bias currents for the bandgap circuit, and establishes proper operating points for all transistors. This multi-functionality eliminates the need for dedicated cascode circuits and separate buffer amplifiers, reducing overall chip area while maintaining high PSRR.
2Reliability
If cascode circuits are used to increase power supply rejection ratio, then PSRR is improved, but voltage headroom is reduced
Solution Approach 1:
The regulator circuit dynamically adjusts its operation based on the available voltage headroom. The control transistor automatically modulates its resistance to maintain proper current flow through the bandgap circuit, adapting to varying supply voltages and temperature conditions without requiring fixed cascode structures that consume excessive headroom.
3Adaptability or versatility
If voltage buffers are used to generate multiple output reference voltages, then multiple reference voltages are provided, but power consumption increases and chip area increases
Solution Approach 1:
The patent segments the voltage reference generation by using a single bandgap core that produces a primary reference voltage, then uses resistive dividers and selective tapping points to generate multiple output voltages (VREF1, VREF2, VREF3) without requiring separate buffer amplifiers for each output. This segmentation approach reduces power consumption while maintaining versatility.
Solution Approach 2:
Resistive divider networks serve as intermediary elements between the single bandgap reference source and multiple output nodes. These passive resistive networks provide voltage scaling and multiplication functions without requiring active buffer circuits, thereby reducing power consumption and chip area while still delivering multiple reference voltages with adequate drive capability.
4Adaptability or versatility
If voltage buffers are used to generate multiple output reference voltages, then multiple reference voltages are provided, but chip area increases
Solution Approach 1:
The patent merges the functions of voltage buffering, voltage scaling, and multiple output generation into a single resistive divider network. This passive network simultaneously provides multiple reference voltages with appropriate drive capability, eliminating the need for multiple separate buffer amplifier circuits and significantly reducing the required chip area.
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 provides a high power supply rejection ratio, reduces chip area, and minimizes power consumption while maintaining stability against temperature and power supply variations, eliminating the need for cascode configurations and voltage buffers, thus achieving improved performance and efficiency.
Implementation Method 1
The bandgap voltage reference is generated by adding the voltage of a forward-biased PN junction having a negative temperature coefficient to a voltage difference of two forward-biased base-emitter PN junctions having a positive temperature coefficient
Implementation Method 2
The voltage signal generated by the bandgap voltage reference supply circuit is amplified by a high gain amplifier circuit
Implementation Method 3
A voltage regulator composed of a FET is used to regulate the power supply voltage
Data Source
AI summary
A voltage generator is used for generating a voltage reference with high power supply rejection. One embodiment of the circuit includes a voltage regulator and a bandgap voltage circuit and an amplifier. The voltage regulator including an input node is coupled to an external power supply for generating a regulated voltage source. A bandgap voltage circuit includes a first and a second resistor and a first and a second transistor to generate a voltage difference between the base-to-emitter voltages of the first and the second transistors. The second resistor is coupled to the first resistor and the first transistor for generating the first predetermined voltage in response to the voltage difference. An amplifier circuit is coupled to the first transistor of the bandgap voltage circuit for receiving a first amplifying signal and generating an amplified signal so as to regulate the regulated voltage source.