CN203839918U - Low-voltage direct current load overloading measurement and control circuit - Google Patents

Abstract

The utility model relates to a low-voltage direct current load overloading measurement and control circuit. The low-voltage direct current load overloading measurement and control circuit comprises a measurement and control main circuit and an overloading discrimination circuit, and specifically comprises a drive DR, a direct current load DL, a thyristor VT1, a MOS transistor VT2, a voltage-stabilizing tube DW1, a voltage-limiting tube DW2, a comparator IC1, an inductor L1, a diode D1, a power supply lamp LED 1, an output lamp LED2, a voltage-stabilizing resistor R1, an anode resistor R2, a grid resistor R3, an output resistor R4, a gate resistor R5, a voltage-stabilizing capacitor C1, a filtering capacitor C2 and a preset capacitor C3 etc. According to the low-voltage direct current load overloading measurement and control circuit, power field effect transistors with ultra-low conduction resistance are employed to serve as current detection components and circuit switch-off control components, the half-control characteristic of the thyristor and a micro-inductor and a rapid discrimination circuit connected in series in a load loop are combined so that real-time detection, discrimination and safety control of overloading and short circuit faults of the low-voltage direct current load are realized, and the low-voltage direct current load overloading measurement and control circuit is advantaged by simple structure, safety, reliability, and low cost.

Description

A kind of low-voltage direct load overload telemetry circuit

Technical field

The utility model belongs to industrial measurement and control field, relates to a kind of circuit, and particularly a kind of low-voltage direct load overload telemetry circuit is applicable to carry out detecting in real time and the occasion of safety protection control to the overload of low-voltage direct load or short trouble.

Background technology

Giving in the power supply of low-voltage direct load with DC driven power supply (also claiming driver); often occur to damage DC driven power supply and load itself because of load overload or the phenomenon that is short-circuited; therefore, must carry out overload and short trouble to detect in real time and safety protection control.Conventional effective ways are at present: by responding Hall current sensor rapidly, load current is detected in real time, relatively judged; in the time exceeding secure threshold, send instruction; turn-off driver and send the instruction of reporting to the police, to realize the safeguard protection to driver, DC load.The problem that the method exists is: the one, and during because of load overload or short trouble, electric current is very large, therefore the power device capacity in driver will be got larger allowance, the range that is used for the Hall current sensor of short-circuit detecting also will select large more morely than running current, and this makes cost very high; The 2nd, for the short trouble that moment occurs, often have little time protection and just will cause the damage of internal drive power device.For this reason, the overload that research cost is low, safe and short trouble testing and control project have important technology and economic implications, and of many uses.

Summary of the invention

The purpose of this utility model is the deficiency existing for prior art, proposes a kind of low-voltage direct load overload telemetry circuit.This circuit utilizes the power field effect pipe (MOSFET) of ultralow conducting resistance, both as current measuring element, also turn-off control element as circuit simultaneously, in conjunction with half control characteristic and the micro-inductance being connected in series and the Quick circuit of thyristor, can realize that overload and short trouble to low-voltage direct load detects in real time, differentiation and security control in load circuit.

The utility model comprises observing and controlling main circuit and overload judging circuit.

Observing and controlling main circuit comprises driver DR, inductance L 1, diode D1, DC load DL, power lights LED1, output lamp LED2, voltage-stabiliser tube DW1, pressure limiting pipe DW2, thyristor VT1, metal-oxide-semiconductor VT2, electric capacity of voltage regulation C1, voltage regulation resistance R1, anode resistance R2, resistance R3, output resistance R4, gate electrode resistance R5, divider resistance R6, positive output end+E end of driver DR and one end of inductance L 1, the negative electrode of diode D1, the anode of power lights LED1, one end of anode resistance R2, one end of resistance R3, the anodic bonding of output lamp LED2, negative output terminal-E of driver DR holds ground connection, and the negative electrode of power lights LED1 is connected with one end of voltage regulation resistance R1, and the other end of voltage regulation resistance R1 connects the negative electrode with voltage-stabiliser tube DW1, one end of electric capacity of voltage regulation C1, one end of pull-up resistor R7, one end of reference resistance R8, the positive power source terminal V+ end of comparator IC1 connects, the anode of voltage-stabiliser tube DW1, the equal ground connection of the other end of electric capacity of voltage regulation C1, the anode of the other end of anode resistance R2 and thyristor VT1, the negative electrode of pressure limiting pipe DW2, the other end of resistance R3, the gate terminal G end of metal-oxide-semiconductor VT2 connects, one end of the gate pole of thyristor VT1 and gate electrode resistance R5, one end of divider resistance R6 connects, the negative electrode of thyristor VT1, the other end of gate electrode resistance R5, the anode of pressure limiting pipe DW2 and the source terminal S of metal-oxide-semiconductor VT2 hold equal ground connection, the drain electrode end D end of metal-oxide-semiconductor VT2 and one end of output resistance R4, negative terminal-IN end of DC load DL, one end of detecting resistance R 11 connects, and the other end of output resistance R4 is connected with the negative electrode of output lamp LED2, anode+IN end of DC load DL and the other end of inductance L 1, the anodic bonding of diode D1.

Overload judging circuit comprises comparator IC1, pull-up resistor R7, reference resistance R8, set resistance R 9, filter resistance R10, detect resistance R 11, filter capacitor C2, set capacitor C 3, the ground end GND end ground connection of comparator IC1, positive input terminal IN+ end and the other end that detects resistance R 11 of comparator IC1, one end of filter resistance R10, one end of filter capacitor C2 connects, the other end of filter resistance R10, the equal ground connection of the other end of filter capacitor C2, the negative input end IN-end of comparator IC1 and the other end of reference resistance R8, set one end of resistance R 9, one end of setting capacitor C 3 connects, set the other end of resistance R 9, set the equal ground connection of the other end of capacitor C 3, the output OUT end of comparator IC1 and the other end of divider resistance R6, the other end of pull-up resistor R7 connects.

The beneficial effects of the utility model are as follows:

The utility model utilizes the power field effect pipe (MOSFET) of a ultralow conducting resistance, both as current measuring element, also turn-off control element as circuit simultaneously, in conjunction with half control characteristic and the micro-inductance being connected in series and the Quick circuit of thyristor, can realize that overload and short trouble to low-voltage direct load detects in real time, Quick and security control in load circuit.This circuit arrangement is simple in structure, safe and reliable, cost is low, applied range.

Brief description of the drawings

Fig. 1 is circuit diagram of the present utility model.

Embodiment

Below in conjunction with accompanying drawing, the utility model is described in further detail.

As shown in Figure 1, low-voltage direct load overload telemetry circuit, comprises observing and controlling main circuit and overload judging circuit.

Observing and controlling main circuit comprises driver DR, inductance L 1, diode D1, DC load DL, power lights LED1, output lamp LED2, voltage-stabiliser tube DW1, pressure limiting pipe DW2, thyristor VT1, metal-oxide-semiconductor VT2, electric capacity of voltage regulation C1, voltage regulation resistance R1, anode resistance R2, resistance R3, output resistance R4, gate electrode resistance R5, divider resistance R6, positive output end+E end of driver DR and one end of inductance L 1, the negative electrode of diode D1, the anode of power lights LED1, one end of anode resistance R2, one end of resistance R3, the anodic bonding of output lamp LED2, negative output terminal-E of driver DR holds ground connection, and the negative electrode of power lights LED1 is connected with one end of voltage regulation resistance R1, and the other end of voltage regulation resistance R1 connects the negative electrode with voltage-stabiliser tube DW1, one end of electric capacity of voltage regulation C1, one end of pull-up resistor R7, one end of reference resistance R8, the positive power source terminal V+ end of comparator IC1 connects, the anode of voltage-stabiliser tube DW1, the equal ground connection of the other end of electric capacity of voltage regulation C1, the anode of the other end of anode resistance R2 and thyristor VT1, the negative electrode of pressure limiting pipe DW2, the other end of resistance R3, the gate terminal G end of metal-oxide-semiconductor VT2 connects, one end of the gate pole of thyristor VT1 and gate electrode resistance R5, one end of divider resistance R6 connects, the negative electrode of thyristor VT1, the other end of gate electrode resistance R5, the anode of pressure limiting pipe DW2 and the source terminal S of metal-oxide-semiconductor VT2 hold equal ground connection, the drain electrode end D end of metal-oxide-semiconductor VT2 and one end of output resistance R4, negative terminal-IN end of DC load DL, one end of detecting resistance R 11 connects, and the other end of output resistance R4 is connected with the negative electrode of output lamp LED2, anode+IN end of DC load DL and the other end of inductance L 1, the anodic bonding of diode D1.

Overload judging circuit comprises comparator IC1, pull-up resistor R7, reference resistance R8, set resistance R 9, filter resistance R10, detect resistance R 11, filter capacitor C2, set capacitor C 3, the ground end GND end ground connection of comparator IC1, positive input terminal IN+ end and the other end that detects resistance R 11 of comparator IC1, one end of filter resistance R10, one end of filter capacitor C2 connects, the other end of filter resistance R10, the equal ground connection of the other end of filter capacitor C2, the negative input end IN-end of comparator IC1 and the other end of reference resistance R8, set one end of resistance R 9, one end of setting capacitor C 3 connects, set the other end of resistance R 9, set the equal ground connection of the other end of capacitor C 3, the output OUT end of comparator IC1 and the other end of divider resistance R6, the other end of pull-up resistor R7 connects.

The all devices including thyristor VT1, metal-oxide-semiconductor VT2, comparator IC1, voltage-stabiliser tube DW1, pressure limiting pipe DW2, power lights LED1, output lamp LED2 etc. that the utility model uses all adopt existing matured product, can obtain by market.For example: thyristor adopts KP1-2, metal-oxide-semiconductor adopts IRF series N-channel MOS FET pipe, and comparator adopts high speed voltage comparator LMV7239, and voltage-stabiliser tube adopts BZX84-B5V1, pressure limiting pipe adopts IN4746A, and power lights, output lamp all adopt 3-5mm light-emitting diode etc.

Main circuit parameter matching relationship in the utility model is as follows:

In accompanying drawing 1, the driver outputting drive voltage U that the utility model is applicable _dscope is+10V--+100V, reference resistance R8, set resistance R 9, filter resistance R10, the parameter matching relationship that detects 11 of resistance R is suc as formula shown in (1), formula (2), filter capacitor C2, set 3 of capacitor C parameter matching relationship as the formula (3), wherein, U _wfor the voltage of voltage regulation (V) of voltage-stabiliser tube DW1, U _icurrent detection signal (V) during for metal-oxide-semiconductor conducting, U _irfor current threshold setting signal (V), R _onfor metal-oxide-semiconductor conducting resistance (Ω), I _omfor overload and the max-thresholds electric current (A) of short-circuit protection.

$\frac{R10}{R10+R11}{U}_i=\frac{R9}{R8+R9}{U}_W=U_{\mathrm{ir}}---\left(1\right)$

U _i＝R _onI _om（2）

$\frac{R10\×R11}{R10+R11}{C}_2=\frac{R8\×R9}{R8+R9}{C}_3---\left(3\right)$

The course of work of the present utility model is as follows:

In the time of driver DR outputting drive voltage, through the effect of voltage-stabiliser tube DW1, produce low pressure voltage of voltage regulation U _was the power supply taking comparator IC1 as main low-power consumption judging circuit, when cause has just powered on, no matter whether conducting of metal-oxide-semiconductor VT2, because making electric current, the effect of inductance L 1 can not suddenly change, now comparator IC1 output low level, and thyristor VT1 is in off state, therefore, metal-oxide-semiconductor VT2 conducting, after this, the possible running status of circuit is as follows:

(1) circuit state while normally work: DC load DL obtains electric work, and load circuit electric current I _obe less than and need protect the overload of control and the max-thresholds electric current I of short-circuit protection _om, comparator IC1 output low level always, thyristor VT1 is always in off state, and metal-oxide-semiconductor VT2 is also always in conducting state, and whole circuit is normally worked;

(2) circuit state while there is overload or short circuit: in the time there is overload or load end short trouble,, after driver DR output voltage and metal-oxide-semiconductor VT2 conducting, through the cushioning effect of inductance L 1, make load circuit electric current I _ocan not suddenly change, and work as I _orise to gradually max-thresholds electric current I _omtime, the output of comparator IC1 becomes high level from low level at once, and thyristor VT1 conducting, metal-oxide-semiconductor VT2 are also turn-offed because the voltage between its grid-source electrode becomes low level from high level, and this has just cut off contacting between driver DR and DC load DL in time, after this, although I _obe zero; make the output of comparator IC1 change to again low level, but due to the half control character (its gate pole can only be controlled conducting, can not control shutoff) of thyristor VT1; make metal-oxide-semiconductor VT2 keep off state, thereby realized the safety protection control to load overload or short trouble.

Claims (3)

1. a low-voltage direct load overload telemetry circuit, comprises observing and controlling main circuit and overload judging circuit, it is characterized in that:

Observing and controlling main circuit comprises driver DR, inductance L 1, diode D1, DC load DL, power lights LED1, output lamp LED2, voltage-stabiliser tube DW1, pressure limiting pipe DW2, thyristor VT1, metal-oxide-semiconductor VT2, electric capacity of voltage regulation C1, voltage regulation resistance R1, anode resistance R2, resistance R3, output resistance R4, gate electrode resistance R5, divider resistance R6, positive output end+E end of driver DR and one end of inductance L 1, the negative electrode of diode D1, the anode of power lights LED1, one end of anode resistance R2, one end of resistance R3, the anodic bonding of output lamp LED2, negative output terminal-E of driver DR holds ground connection, and the negative electrode of power lights LED1 is connected with one end of voltage regulation resistance R1, the negative electrode of the other end of voltage regulation resistance R1 and voltage-stabiliser tube DW1, one end of electric capacity of voltage regulation C1, one end of pull-up resistor R7, one end of reference resistance R8, the positive power source terminal V+ end of comparator IC1 connects, the anode of voltage-stabiliser tube DW1, the equal ground connection of the other end of electric capacity of voltage regulation C1, the anode of the other end of anode resistance R2 and thyristor VT1, the negative electrode of pressure limiting pipe DW2, the other end of resistance R3, the gate terminal G end of metal-oxide-semiconductor VT2 connects, one end of the gate pole of thyristor VT1 and gate electrode resistance R5, one end of divider resistance R6 connects, the negative electrode of thyristor VT1, the other end of gate electrode resistance R5, the anode of pressure limiting pipe DW2 and the source terminal S of metal-oxide-semiconductor VT2 hold equal ground connection, the drain electrode end D end of metal-oxide-semiconductor VT2 and one end of output resistance R4, negative terminal-IN end of DC load DL, one end of detecting resistance R 11 connects, and the other end of output resistance R4 is connected with the negative electrode of output lamp LED2, anode+IN end of DC load DL and the other end of inductance L 1, the anodic bonding of diode D1,

Overload judging circuit comprises comparator IC1, pull-up resistor R7, reference resistance R8, set resistance R 9, filter resistance R10, detect resistance R 11, filter capacitor C2, set capacitor C 3, the ground end GND end ground connection of comparator IC1, positive input terminal IN+ end and the other end that detects resistance R 11 of comparator IC1, one end of filter resistance R10, one end of filter capacitor C2 connects, the other end of filter resistance R10, the equal ground connection of the other end of filter capacitor C2, the negative input end IN-end of comparator IC1 and the other end of reference resistance R8, set one end of resistance R 9, one end of setting capacitor C 3 connects, set the other end of resistance R 9, set the equal ground connection of the other end of capacitor C 3, the output OUT end of comparator IC1 and the other end of divider resistance R6, the other end of pull-up resistor R7 connects.

2. a kind of low-voltage direct load overload telemetry circuit as claimed in claim 1, it is characterized in that: described thyristor VT1, metal-oxide-semiconductor VT2, comparator IC1, voltage-stabiliser tube DW1, pressure limiting pipe DW2, power lights LED1, output lamp LED2 all adopts existing matured product, can obtain by market, described thyristor VT1 adopts KP1-2, metal-oxide-semiconductor VT2 adopts IRF series N-channel MOS FET pipe, comparator IC1 adopts high speed voltage comparator LMV7239, voltage-stabiliser tube DW1 adopts BZX84-B5V1, pressure limiting pipe DW2 adopts IN4746A, power lights LED1, output lamp LED2 all adopts 3-5mm light-emitting diode.

3. a kind of low-voltage direct load overload telemetry circuit as claimed in claim 1, is characterized in that: the driving voltage U of described driver DR output _dscope is+10V～+ 100V, reference resistance R8, set resistance R 9, filter resistance R10, the parameter matching relationship that detects 11 of resistance R is suc as formula shown in (1), formula (2), filter capacitor C2, set 3 of capacitor C parameter matching relationship as the formula (3), wherein, U _wfor the voltage of voltage regulation (V) of voltage-stabiliser tube DW1, U _icurrent detection signal (V), U during for metal-oxide-semiconductor VT2 conducting _irfor current threshold setting signal (V), R _onfor metal-oxide-semiconductor VT2 conducting resistance (Ω), I _omfor overload and the max-thresholds electric current (A) of short-circuit protection;

$\frac{R10}{R10+R11}{U}_i=\frac{R9}{R8+R9}{U}_W=U_{\mathrm{ir}}---\left(1\right)$

U _i＝R _onI _om （2）

$\frac{R10\×R11}{R10+R11}{C}_2=\frac{R8\×R9}{R8+R9}{C}_3---\left(3\right).$