Output control circuit of DC / DC converter

Abstract

The utility model discloses an output control circuit of a DC / DC converter, and aims to solve the problem that the DC / DC converter has no output when any high level of a multipath control end of the DC / DC converter is output. In order to solve the problems that in the prior art, when three paths of control ends are low-level output, a DC / DC converter has output, and the ground of the control ends is in common ground with one path of output and cannot be in common ground with the other path of output, the utility model comprises a resistor R1, a voltage-regulator tube V6, a diode V7 and triodes V5, R2 is a current-limiting resistor, V4 is a voltage-regulator tube, a photoelectric coupler IC1, diodes V1, V2 and V3 are respectively connected with the three paths of control ends, and the photoelectric coupler IC1 is connected with the three paths of control ends. The DC / DC converter is ingenious in design, the anti-interference performance and the isolation performance of the photoelectric coupler are good, and the DC / DC converter achieves the purposes that the DC / DC converter does not output when the level of the control end is high and the DC / DC converter outputs when the level of the control end is low through devices such as the pulse width modulator.

Description

Technical Field

[0001] The utility model relates to the technical field of DC / DC converters, in particular to an output control circuit of a DC / DC converter. Background Art

[0002] At present, the control function of the DC / DC converter used in the whole system is the user's demand indicator. When the DC / DC converter is given multiple control voltages externally, if one of them is high level, the DC / DC converter will not work, and if all the other voltages are low level, the DC / DC converter will work normally, and the ground of the external voltage is connected to the output ground of the DC / DC converter. This function can improve the reliability and safety of the DC / DC converter.

[0003] The output control circuit of the traditional DC / DC converter uses transistors and lacks optocouplers, and has poor anti-interference performance and isolation. The traditional circuit is simple and saves space, but its disadvantage is that it is not suitable for the situation where the DC / DC converter has multiple outputs without a common ground, and it cannot achieve the function of controlling all outputs of the DC / DC converter when the control end is at a high level. Utility Model Content

[0004] In order to solve the problem that the multiple outputs of the DC / DC converter do not share a common ground, the DC / DC converter has no output voltage when one of the three control terminals is at a high level, and the DC / DC converter outputs normally when all three control terminals are at a low level.

[0005] The technical solution of the utility model is an output control circuit of a DC / DC converter, including a photocoupler IC1, a pulse width modulator, a resistor R1, a current limiting resistor R2, a voltage regulator tube V6, a voltage regulator tube V4, a diode V1, a diode V2, a diode V3, a triode V5, and a diode V7;

[0006] The emitter end of the photocoupler IC1 is connected to the cathode of the voltage regulator tube V6, the collector end and the cathode end of the photocoupler IC1 are connected to the output ground, and the anode end of the photocoupler IC1 is connected to the current limiting resistor R2;

[0007] The cathode of the diode V7 is connected to the collector of the transistor V5, and the emitter of the transistor V5 is connected to the VCC port of the pulse width modulator; the anode of the diode V7 is connected to the resistor R1, and the resistor R1 and the anode of the diode V7 are connected to the Vin+ terminal; the resistor R1 is connected to the base of the diode V7, the emitter of the photocoupler IC1, and the cathode of the voltage regulator tube V6;

[0008] The current limiting resistor R2 is connected to the anode of the voltage regulator tube V4, the cathode of the voltage regulator tube V4 is connected to the cathodes of the diodes V1, V2 and V3 respectively, and the anodes of the diodes V1, V2 and V3 are connected to the control terminals Con1, Con2 and Con3 respectively.

[0009] The resistor R1, the voltage regulator tube V6, the diode V7 and the transistor V5 form a linear power supply circuit.

[0010] The utility model has the following beneficial effects:

[0011] The utility model has an ingenious circuit design and realizes the output control function of the DC / DC converter by combining devices such as a photoelectric coupler, a pulse width modulator and a triode.

[0012] The utility model saves space, is not affected by other circuits, does not affect other internal circuits, and the VCC ports of the internal pulse width modulators of the multi-channel output power supply are connected together, and can also be used as the multi-channel output control end of the DC / DC converter.

[0013] The utility model has good output control capability, and can solve the multi-channel output control function of the DC / DC converter used in the whole system by shutting down the VPP end of the pulse width modulator of the DC / DC converter. At the same time, the universality of the scheme is good, and the voltage value range of the high level and the low level required to control the DC / DC converter in different situations can be realized by simply changing the resistance parameters. The design scheme of this function is simple and universal, and has a good promotion space and a wider application field. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the circuit principle of the utility model. DETAILED DESCRIPTION

[0015] The utility model is described in detail below in conjunction with the accompanying drawings.

[0016] In order to make the purpose, technical solution and advantages of the utility model clearer, the technical solution of the utility model will be described in detail below. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other implementation methods obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0017] like Figure 1As shown: an output control circuit of a DC / DC converter, including a photocoupler IC1 and a pulse width modulator, characterized in that: it also includes a resistor R1, a current limiting resistor R2, a voltage regulator tube V6, a voltage regulator tube V4, a diode V1, a diode V2, a diode V3, a transistor V5, and a diode V7;

[0018] The emitter end of the photocoupler IC1 is connected to the cathode of the voltage regulator tube V6, the collector end and the cathode end of the photocoupler IC1 are connected to the output ground, and the anode end of the photocoupler IC1 is connected to the current limiting resistor R2;

[0019] The cathode of the diode V7 is connected to the collector of the transistor V5, and the emitter of the transistor V5 is connected to the VCC port of the pulse width modulator; the anode of the diode V7 is connected to the resistor R1, and the resistor R1 and the anode of the diode V7 are connected to the Vin+ terminal; the resistor R1 is connected to the base of the diode V7, the emitter of the photocoupler IC1, and the cathode of the voltage regulator tube V6;

[0020] The resistor current limiting R2 is connected to the anode of the voltage regulator tube V4, the cathode of the voltage regulator tube V4 is connected to the cathodes of the diodes V1, V2 and V3 respectively, and the anodes of the diodes V1, V2 and V3 are connected to the control terminals Con1, Con2 and Con3 respectively.

[0021] The resistor R1, the voltage regulator tube V6, the diode V7 and the transistor V5 form a linear power supply circuit

[0022] When connected: The utility model provides an output control circuit of a DC / DC converter, including a linear power supply circuit composed of a resistor R1, a voltage regulator tube V6 and a transistor V5, which realizes the output control function of the DC / DC converter by combining the characteristics of the photoelectric coupler IC1 with a pulse width modulator, and R2 is a current limiting resistor;

[0023] The emitter of the photocoupler IC1 is connected to the cathode of the voltage regulator tube V6, the collector of the photocoupler IC1 is connected to the input ground, the cathode of the photocoupler IC1 is connected to the output ground, and the anode of the photocoupler IC1 is connected to the current limiting resistor R2;

[0024] The emitter of transistor V5 is connected to the VCC port of the pulse width modulator, the anode of voltage regulator V4 is connected to the current limiting resistor R2, the cathode of voltage regulator V4 is connected to the cathodes of diodes V1, V2 and V3 respectively, and the anodes of V1, V2 and V3 are connected in parallel to the three-way control terminal;

[0025] The photocoupler IC1 uses the detected output voltage change to control the VCC terminal of the pulse width modulator IC1 to realize the function of the output control terminal.

[0026] The specific process is as follows: the input and output of the photocoupler are isolated from each other. When one of the Vcon is at a high level, the input photodiode receives an external signal and conducts, and its current changes, thereby changing the working state of the transistor, causing the output electrical signal to change, pulling down the base voltage of the transistor V5, causing the VCC terminal voltage of the pulse width modulator to become lower, and the pulse width modulator in the circuit does not work and has no output; on the contrary, when the three Vcon are all low levels, the input photodiode does not work, the optocoupler does not conduct, and the output circuit does not affect the base voltage of the transistor V5. The emitter voltage of the transistor V5 is approximately the voltage of the voltage regulator tube minus the voltage drop, which is the power supply voltage of the VCC terminal of the pulse width modulator. The pulse width modulator works normally and has output. By simply changing the resistance and voltage regulator tube parameters, the voltage value range of the control terminal required in different situations of the DC / DC converter can be realized to meet different performance index requirements.

[0027] The utility model is a linear power supply circuit composed of a resistor R1, a voltage regulator tube V6, a diode V7 and a transistor V5, R2 is a current limiting resistor, V4 is a voltage regulator tube, a photoelectric coupler IC1 plays an isolation feedback role, diodes V1, V2 and V3 are respectively isolated three-way control terminals, the emitter of the transistor V5 is connected to the VCC port of the pulse width modulator, when the collector terminal voltage value of the transistor V5 is lower than the threshold voltage of the pulse width modulator, the DC / DC converter has no output; when the collector terminal voltage value of the transistor V5 is higher than the threshold voltage of the pulse width modulator, the DC / DC converter has output.

[0028] The utility model discloses an output control circuit of a DC / DC converter. The circuit controls the voltage value of the VCC terminal of a pulse width modulator through the voltage value output by a photoelectric coupler, so that the DC / DC converter meets the electrical performance characteristics of controlling the output voltage by a multi-channel output control terminal. The circuit has the advantages of simple components, good versatility, flexible application, etc.

[0029] The above is only a specific implementation of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a technician familiar with the field within the technical scope disclosed in the present invention should be included in the protection scope of the present invention.

Claims

1. An output control circuit of a DC / DC converter, comprising a photocoupler IC1 and a pulse width modulator, characterized in that: It also includes resistor R1, current limiting resistor R2, voltage regulator V6, voltage regulator V4, diode V1, diode V2, diode V3, transistor V5, and diode V7; The emitter end of the photocoupler IC1 is connected to the cathode of the voltage regulator tube V6, the collector end and the cathode end of the photocoupler IC1 are connected to the output ground, and the anode end of the photocoupler IC1 is connected to the current limiting resistor R2; The cathode of the diode V7 is connected to the collector of the transistor V5, and the emitter of the transistor V5 is connected to the VCC port of the pulse width modulator; the anode of the diode V7 is connected to the resistor R1, and the resistor R1 and the anode of the diode V7 are connected to the Vin+ terminal; the resistor R1 is connected to the base of the diode V7, the emitter of the photocoupler IC1, and the cathode of the voltage regulator tube V6; The current limiting resistor R2 is connected to the anode of the voltage regulator tube V4, the cathode of the voltage regulator tube V4 is connected to the cathodes of the diodes V1, V2 and V3 respectively, and the anodes of the diodes V1, V2 and V3 are connected to the control terminals Con1, Con2 and Con3 respectively.

2. The output control circuit of a DC / DC converter according to claim 1, characterized in that: The resistor R1, the voltage regulator tube V6, the diode V7 and the transistor V5 form a linear power supply circuit.

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