CN205374575U

CN205374575U - Low -power consumption current sampling circuit

Info

Publication number: CN205374575U
Application number: CN201620082729.2U
Authority: CN
Inventors: 朱晓平
Original assignee: Xfrmtronics Technologies Co Ltd
Current assignee: Xfrmtronics Technologies Co Ltd
Priority date: 2016-01-27
Filing date: 2016-01-27
Publication date: 2016-07-06
Anticipated expiration: 2026-01-27

Abstract

The utility model discloses a low -power consumption current sampling circuit, including the reference voltage module that is used for providing reference voltage, the reference voltage module is connected with two filter capacitance C1, C2, filter capacitance C1, C2 sets up respectively at the input of reference voltage module and output, the reference voltage module still is connected with the divider resistance R1 and the divider resistance R3 of series connection, divider resistance R1 and divider resistance R3's junction is equipped with parallelly connected comparator and decoupling capacitor, the equal ground connection of the other end of decoupling capacitor and comparator, divider resistance R3's other end linked switch pipe and the sampling resistor R2 who is used for overflowing the sample, sampling resistor R2's one end linked switch pipe, and the other terminal of the capacitor is connected to the ground. The utility model discloses a divider resistance R1 and divider resistance R3's stack voltage reduces sampling resistor R2's voltage, has reduced sampling resistor R2's resistance value to make its power is reduced, can not generate heat because of extra consumption, reduce the temperature and float, improved reliability of an item.

Description

Low power consumption current sample circuit

Technical field

This utility model relates to current sampling circuit technical field, particularly relates to a kind of low power consumption current sample circuit.

Background technology

Many circuit designers problem through being commonly encountered overcurrent sample, when particularly sampling resistor and electric current are bigger, sampling resistor is excessive and produces big extra power consumption and generates heat, and not only heating is difficult to process, also lead to temperature drift excessive, affect product index and reduce the reliability of product.

Utility model content

The utility model proposes a kind of low power consumption current sample circuit, solve the heating of sampling resistor and the problem that temperature drift is excessive.

The technical solution of the utility model is achieved in that

A kind of low power consumption current sample circuit, including the reference voltage module for providing reference voltage, reference voltage module is connected to two filter capacitor C1, C2, filter capacitor C1, C2 is separately positioned on input and the outfan of reference voltage module, reference voltage module is also associated with the divider resistance R1 and divider resistance R3 of series connection, the junction of divider resistance R1 and divider resistance R3 is provided with comparator and the decoupling capacitor of parallel connection, the equal ground connection of the other end of decoupling capacitor and comparator, the other end connecting valve pipe of divider resistance R3 and the sampling resistor R2 for overcurrent sample, one end connecting valve pipe of sampling resistor R2, other end ground connection.

Further, reference voltage module adopts low pressure difference linear voltage regulator to constitute.

Further, over-current signal is sent to processor by comparator.

Further, over-current signal is sent to processor by comparator through communication module.

Further, communication module is wireless communication module.

Further, the setting value of sampling resistor R2 voltage is identical with the turnover voltage of the partial pressure value sum of divider resistance R3 Yu comparator.

The beneficial effects of the utility model are in that: reduced the voltage of sampling resistor R2 by the superimposed voltage of divider resistance R1 and divider resistance R3, reduce the resistance value of sampling resistor R2, so that its power reduces, will not generate heat because of extra power consumption, drop Low Drift Temperature, improve the reliability of product.

Accompanying drawing explanation

In order to be illustrated more clearly that this utility model embodiment or technical scheme of the prior art, the accompanying drawing used required in embodiment or description of the prior art will be briefly described below, apparently, accompanying drawing in the following describes is only embodiments more of the present utility model, for those of ordinary skill in the art, under the premise not paying creative work, it is also possible to obtain other accompanying drawing according to these accompanying drawings.

Fig. 1 is the circuit theory diagrams of this utility model one embodiment of low power consumption current sample circuit.

Detailed description of the invention

Below in conjunction with the accompanying drawing in this utility model embodiment, the technical scheme in this utility model embodiment is clearly and completely described, it is clear that described embodiment is only a part of embodiment of this utility model, rather than whole embodiments.Based on the embodiment in this utility model, the every other embodiment that those of ordinary skill in the art obtain under not making creative work premise, broadly fall into the scope of this utility model protection.

As it is shown in figure 1, the utility model proposes a kind of low power consumption current sample circuit, including the reference voltage module for providing reference voltage, concrete, reference voltage module adopts low pressure difference linear voltage regulator U1 to constitute.Reference voltage module is provided with three terminals, respectively input, output and ground.

Reference voltage module is connected to two filter capacitors C1, C2, filter capacitor C1, C2 are separately positioned on input and the outfan of reference voltage module, the input of reference voltage module is connected to DC voltage, and one end of filter capacitor C1 connects DC voltage and reference voltage module, other end ground connection.One end of filter capacitor C2 connects the outfan of reference voltage module, other end ground connection.

Reference voltage module is also associated with the divider resistance R1 and divider resistance R3 of series connection, the junction of divider resistance R1 and divider resistance R3 is provided with the comparator U2 and decoupling capacitor C3 of parallel connection, the equal ground connection of the other end of decoupling capacitor C3 and comparator U2, the input of comparator U2 has two terminals, one terminal is connected with decoupling capacitor C3, and another terminal is turnover voltage Vref.

One end connecting valve pipe of the other end connecting valve pipe of divider resistance R3 and sampling resistor R2, sampling resistor R2 for overcurrent sample, other end ground connection.

The setting value of sampling resistor R2 voltage is identical with the turnover voltage of the partial pressure value sum of divider resistance R3 Yu comparator U2.If the partial pressure value sum of the sampled voltage of sampling resistor R2 and resistance R3 reaches setting voltage, then comparator U2 upset, produce and output overcurrent signal.

Comparator U2 output overcurrent signal is provided with two kinds of approach, and one is that over-current signal is directly sent to processor by comparator U2.Another is that over-current signal is sent to processor by comparator through communication module.

Concrete, communication module is wireless communication module or wire communication module, and wireless communication module can adopt bluetooth communication module or infrared communication module or radio-frequency communication module etc..

Giving an example, sampled voltage is that 0.2V realizes 10A overcurrent protection

-Vref=0.2V

-Imax=10A

If design traditionally, sampling resistor R2 takes 20m Ω, then power consumption is 2W, need to select 5W resistance.

If adopting circuit theory diagrams of the present utility model, the predeterminable 0.15V of sampled voltage, as long as then sampling resistor 0.05V can meet the mistake flow point of 0.2V, circuit parameter is as follows:

-LDO=3.3VLDO is reference voltage

-R1=10K Ω

-R3=153.85 Ω

Then, the power consumption of sampling resistor R2 is 0.5W, can be selected for 1W resistance.

Compared with prior art, technical solutions of the utility model have the following advantages this utility model

-reduce sampling voltage, reduce power consumption, especially for low-voltage, the application of big electric current

-reduce temperature rise, drop Low Drift Temperature, improve overcurrent protection precision

-improve efficiency

-reliability is higher

-available more small package and power device, reduces cost

The foregoing is only preferred embodiment of the present utility model; not in order to limit this utility model; all within spirit of the present utility model and principle, any amendment of making, equivalent replacement, improvement etc., should be included within protection domain of the present utility model.

Claims

1. a low power consumption current sample circuit, it is characterized in that: include the reference voltage module for providing reference voltage, described reference voltage module is connected to two filter capacitor C1, C2, described filter capacitor C1, C2 is separately positioned on input and the outfan of described reference voltage module, described reference voltage module is also associated with the divider resistance R1 and divider resistance R3 of series connection, the junction of described divider resistance R1 and divider resistance R3 is provided with comparator and the decoupling capacitor of parallel connection, the equal ground connection of the other end of described decoupling capacitor and described comparator, the other end connecting valve pipe of described divider resistance R3 and the sampling resistor R2 for overcurrent sample, one end of described sampling resistor R2 connects described switching tube, other end ground connection.

2. low power consumption current sample circuit according to claim 1, it is characterised in that: described reference voltage module adopts low pressure difference linear voltage regulator to constitute.

3. low power consumption current sample circuit according to claim 1, it is characterised in that: over-current signal is sent to processor by described comparator.

4. low power consumption current sample circuit according to claim 1, it is characterised in that: over-current signal is sent to processor by described comparator through communication module.

5. low power consumption current sample circuit according to claim 4, it is characterised in that: described communication module is wireless communication module.

6. low power consumption current sample circuit according to claim 1, it is characterised in that: the setting value of described sampling resistor R2 voltage is identical with the turnover voltage of the partial pressure value sum of divider resistance R3 Yu described comparator.