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Symmetrically Matched Voltage Mirror and Applications Therefor對稱配對電壓鏡及其應用

To implement a voltage mirror, a high-gain high-speed operational amplifier should be used. However, the design of such amplifier is very difficult and complex.

The invention proposed symmetrically matched transistor structures to implement voltage mirrors which have high accuracy, high speed and wide dynamic range. The structure is simple as only a few transistors are required.

The present invention is performed with zero systematic offset by employing a symmetrically matched structure. No frequency compensation capacitor is needed for stability. The present invention does not need any cascode struture, and the voltage mirrors can operate with a very low supply voltage. The circuit complexity of this invention is much lower and the mirroring process is fast enough for applications such as current sensing in switching converters with a low switching frequency.

The voltage mirrors invented can be used in many analog integrated circuit functional blocks such as bandgap references, low dropout regulations, current mirrors, current conveyors and current sensors.
Technology Benefits
1. Much lower circuit complexity and size with better performance
2. Higher accuracy
3. Higher power supply rejection
4. No compensation capacitor required
5. Simpler structure in low-cost CMOS process
6. Requires only lower supply voltage
Technology Application
- Power management
- Integrated circuits for portable electronic devices such as mobile phones, PDAs, MP3 players and laptop computers
- Communication products
Supplementary Information
Patent Number: US7215187B2
Application Number: US2005185294A
Inventor: Lam, Yat Hei | Ki, Wing Hung | Tsui, Chi Ying
Priority Date: 23 Jul 2004
Priority Number: US7215187B2
Application Date: 20 Jul 2005
Publication Date: 8 May 2007
IPC Current: G05F000110
US Class: 327543
Assignee Applicant: The Hong Kong University of Science & Technology
Title: Symmetrically matched voltage mirror and applications therefor
Usefulness: Symmetrically matched voltage mirror and applications therefor
Summary: For current sensor used in switching converter for current mode control and overcurrent protection, bandgap reference circuit, low dropout regulator, current mirror and current conveyor.
Novelty: Symmetrically matched voltage mirror circuit for use in e.g. current sensor, has four transistor pairs having same aspect ratio
Sub Category
Circuit Design
Application Date
20 Jul 2005
Application No.
US 11/185294
Patent Information
US 7215187
ID No.
Hong Kong

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