Bandgap Voltage Reduction Circuit for Low-Voltage Temperature Stability
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Solution Overview
Problem
Existing bandgap reference voltage circuits face challenges in generating a temperature-independent reference voltage lower than 1.25V, as current solutions like buffers, resistors, and voltage followers either consume large power, occupy significant area, or have poor temperature characteristics.
Innovation Solution
A voltage reduction circuit incorporating a first transistor, current mirror circuit, voltage dividing circuit, output resistor, and fourth transistor, which forms a current mirror to generate a reference voltage independent of temperature and lower than the initial bandgap reference voltage, using a simple circuit structure with minimal power and area consumption without additional pins or external components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If buffers and resistors are used to reduce bandgap reference voltage, then voltage reduction is achieved, but power consumption and circuit area increase significantly
Solution Approach 1:
The patent changes the operating parameters of transistors (current mirrors, voltage dividing ratios) to achieve voltage reduction without requiring large buffers or resistors. By adjusting the current mirror ratio and voltage divider configuration, the circuit reduces the reference voltage from the standard 1.25V to a lower value while maintaining low power consumption and compact area.
2Temperature
If voltage follower is used to reduce bandgap reference voltage, then voltage reduction is achieved, but temperature characteristic deteriorates
Solution Approach 1:
The patent introduces a voltage dividing circuit as an intermediary between the bandgap reference voltage source and the output. This voltage divider, combined with the current mirror, acts as a mediator that reduces the voltage while preserving the temperature-independent characteristic of the original bandgap reference, unlike a simple voltage follower which directly degrades temperature performance.
3Area of stationary object
If voltage dividing resistors are used to directly divide bandgap reference voltage, then voltage reduction is achieved, but circuit area increases or voltage characteristic is affected
Solution Approach 1:
The patent merges the voltage dividing function with the current mirror circuit into a single integrated structure. Instead of using separate large resistors for voltage division, the design combines transistor-based current mirroring with voltage division, achieving both voltage reduction and low area occupation in one unified circuit block.
Data Source
AI summary
A voltage reduction circuit for a bandgap reference voltage circuit is provided, and the voltage reduction circuit includes a first transistor, a current mirror circuit, a voltage dividing circuit, an output resistor, and a fourth transistor. The first transistor receives an initial bandgap reference voltage from the bandgap reference voltage circuit. The voltage dividing circuit has a voltage dividing node for outputting a first dividing voltage. The fourth transistor receives the first divided voltage. The current mirror circuit forms a first current on the voltage dividing circuit through the first transistor, and mirrors the first current to the output resistor to form a second current. The voltage dividing circuit and the output resistor each have a first temperature characteristic, the first transistor and the fourth transistor each have a second temperature characteristic, thereby generating, a reference voltage independent of temperature and lower than the initial bandgap reference voltage.