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Low-dropout linear switch with current detecting and current limiting functions

A low-dropout linear and current detection technology, applied in the field of low-dropout linear switches and analog integrated circuits, can solve the problems of increasing static power consumption of linear switches, large device size, and damage to PMOS tube M1, etc.

Active Publication Date: 2013-11-06
XIDIAN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] Although the above-mentioned traditional linear switch has a simple structure, the size of the device used is large and the chip area is large; in addition, the traditional linear switch has the following disadvantages: 1) When the output terminal is short-circuited, the current flowing through the PMOS transistor M1 is very large It is likely to damage the PMOS tube M1; 2) When the control signal EN is high and the output voltage V OUT In the no-load state, there is current through the resistor R 1 And the NMOS tube M2 flows to the ground, increasing the static power consumption of the linear switch

Method used

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  • Low-dropout linear switch with current detecting and current limiting functions
  • Low-dropout linear switch with current detecting and current limiting functions
  • Low-dropout linear switch with current detecting and current limiting functions

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Embodiment 1

[0046] refer to figure 2 , the low dropout linear switch of the present invention includes a reference voltage current generation unit 1 , an error amplifier 2 , an operational amplifier 3 and a current sampling unit 4 . in:

[0047] Reference voltage current generation unit 1, which uses a conventional bandgap reference structure to generate a reference voltage V with zero temperature coefficient REF , by reference voltage V REF After the voltage-to-current conversion, the conventional current mirror structure is used to generate a bias current I with zero temperature coefficient 1 ~I 5 ;

[0048] The error amplifier 2 is provided with four input terminals a, b, c, d and one output terminal e; the input terminal a is connected to the feedback voltage V input by the current sampling unit 4 FB ; The input terminal b is connected to the reference voltage V input by the reference voltage current generating unit 1 REF ; The input terminal c is connected to the bias current ...

Embodiment 2

[0077] The present invention includes a reference voltage and current generation unit 1, an error amplifier 2, an operational amplifier 3 and a current sampling unit 4, wherein the reference voltage and current generation unit 1, the error amplifier 2, and the current sampling unit 4 are the same as those in Embodiment 1.

[0078] refer to Figure 6 , the operational amplifier 3 of the present invention includes 8 low-voltage NMOS transistors M 601 ~ M 605 , M 611 ~ M 613 , 3 low-voltage PMOS tubes M 608 ~ M 610 , 2 high-voltage NMOS tubes M 606 and M 607 and resistance R 4 . in:

[0079] Low voltage NMOS tube M 611 ~ M 613 connected in series, for the high voltage NMOS tube M 606 and M 607 Provide bias voltage; low voltage NMOS tube M 613 The source is grounded, and its drain is connected to the low-voltage NMOS transistor M 612 The source; low-voltage NMOS tube M 612 The drain is connected to the low-voltage NMOS transistor M 611 The source; low-voltage NMOS...

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Abstract

The invention discloses a low-dropout linear switch with current detecting and current limiting functions and mainly solves the problems of high static power consumption and short-circuit protection in the prior art. The low-dropout linear switch comprises a reference voltage and current generation unit (1), an error amplifier (2), an operational amplifier (3) and a current sampling unit (4). The reference voltage and current generation unit (1) generates reference voltages and bias currents of the zero temperature coefficient; the current sampling unit (4) is used for sampling output currents to obtain output voltages, voltage sampling signals and feedback voltages, wherein the output voltages and the voltage sampling signals are regulated through the operational amplifier (3), so that the voltage sampling signals are 24mV higher than the output voltages; the error amplifier (2) is used for amplifying difference values between the feedback voltages and the reference voltages and outputting error amplifying signals to the current sampling unit (4) so as to constitute a negative feedback loop and limit values of the output currents. By the aid of the low-dropout linear switch, accurate control of the output currents is achieved, static power consumption of the linear switch is reduced, and the low-dropout linear switch can be used for controlling connection and disconnection of a converter and a battery.

Description

technical field [0001] The invention belongs to the technical field of electronic circuits, and relates to an analog integrated circuit, in particular to a low-dropout linear switch with current detection and current limiting functions, which can be used for switching between a converter and a battery. Background technique [0002] With the rapid development of portable devices, people pay more and more attention to battery life. Linear switches are increasingly used in the connection between DC-DC converters and batteries. Linear switches have many advantages, such as low leakage current, extremely small quiescent current, small size, and strong anti-electromagnetic interference ability, especially their output voltage It is nearly equal to the input voltage, which plays an important role in prolonging the battery life and saving energy. [0003] Traditional linear switch structures such as figure 1 As shown, it includes a high-voltage PMOS transistor M1, a high-voltage N...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H03K17/687
Inventor 来新泉邵丽丽李演明李志鑫
Owner XIDIAN UNIV