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Start-up circuit for bandgap circuit

A technology of starting circuit and starting voltage, which is applied in the direction of adjusting electrical variables, control/regulating systems, instruments, etc., can solve the problems of unsuitable bandgap use of circuits, etc., and achieve the effect of not being easily affected by processing changes.

Inactive Publication Date: 2009-09-02
ITI SCOTLAND
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

While the circuit is suitable for use at the zero convergence point, the circuit is not suitable for use near the bandgap at the diode threshold because this point will change due to temperature and processing variations

Method used

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  • Start-up circuit for bandgap circuit
  • Start-up circuit for bandgap circuit
  • Start-up circuit for bandgap circuit

Examples

Experimental program
Comparison scheme
Effect test

Embodiment Construction

[0026] image 3 is a diagram of a bandgap circuit 2 and a start-up circuit 4 according to the invention.

[0027] The bandgap circuit 2 includes a positive supply voltage 21 , such as a 1.2V or 1.5V supply voltage; and a PMOS transistor 22 .

[0028] The bandgap circuit also includes a first bandgap diode 23 connected in parallel with a resistor 24 . The sampled voltage A is taken across the resistor 24 .

[0029] The bandgap circuit also includes a plurality of bandgap diodes 25 connected in series with a resistor 26 . This combination is also connected in parallel with a resistor 27 . The sampled voltage B is taken across the resistor 27 .

[0030] The sampled voltages A and B are input to an operational amplifier 28 whose output is connected to the PMOS transistor 22 . Another resistor 29 is connected between the PMOS transistor 22 and ground and produces the output bandgap voltage.

[0031] Bandgap circuit 2 generates a precise reference voltage. However, as mention...

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PUM

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Abstract

A start-up circuit is provided for a bandgap circuit, the bandgap circuit having at least one bandgap diode. The start-up circuit comprises a comparator for providing a start-up voltage for the bandgap circuit. The comparator is connected to receive a first reference voltage at a first input terminal, the output of the comparator being connected in a feedback loop to its second input terminal. A reference voltage circuit is provided for generating the first reference voltage for the first input terminal of the comparator. The reference voltage circuit comprises a start-up circuit diode that is matched with the at least one bandgap diode in the bandgap circuit. As such, any temperature and / or process variations in the bandgap diode are matched by the start-up circuit diode, thereby providing an accurate and reliable reference voltage, and hence start-up voltage for the bandgap circuit.

Description

technical field [0001] The present invention relates to start-up circuits for bandgap circuits and, in particular, to start-up circuits for low-voltage bandgap circuits used in ultra-wideband devices. Background technique [0002] UWB is a radio technology that transmits digital data across a very wide frequency range of 3.1GHz-10.6GHz. It utilizes ultra-low transmission power typically below -41dBm / MHZ, allowing the technology to be completely hidden under other transmission frequencies such as existing Wi-Fi, GSM and Bluetooth. This means UWB can coexist with other radio frequency technologies. However, this has the limitation of limiting communication to a distance of typically 5 to 20 meters. [0003] There are two schemes for implementing UWB: a time-domain scheme, which constructs signals with pulse waveforms characteristic of UWB; and a frequency-domain modulation scheme, which uses traditional FFT-based Orthogonal Frequency Division Multiplexing (OFDM) over multipl...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G05F3/30
CPCG05F3/30G05F1/461G05F1/562
Inventor 艾安·维德勒
Owner ITI SCOTLAND