Utility model content
Technical problem to be solved in the utility model is to avoid the weak point in above-mentioned background technology and a kind of power supply switch controller of the surge current that prevents from starting shooting is provided.The utlity model has the advantages such as anti-start surge current, output overcurrent protection, remote-controlled startup.
Technical problem to be solved in the utility model is realized by following technical scheme:
1, a power supply switch controller, comprise field effect transistor 1, inductor 2, filter 3, current sampling unit 4, EFT Drive Unit 5, fly-wheel diode 6, with non-buffer 7, pulse-width modulation circuit 8, amplify comparison circuit 9, the second accessory power supply 10 and the first accessory power supply 11; It is characterized in that: the direct current of outside input is connected to the drain electrode of field effect transistor 1, by the source electrode of field effect transistor 1, export inductor 2 one end to, the other end of inductor 2 is connected to filter 3, the negative electrode of fly-wheel diode 6 is connected to the source electrode of field effect transistor 1, composition main circuit topology, i.e. adjusting and voltage-reduction switch voltage stabilizing circuit; The output signal of external logic control level and pulse-width modulation circuit 8 transfers to the input with non-buffer 7, carry out NAND Logic computing, signal level after computing is by being connected to the inverting input of EFT Drive Unit 5 with the output of non-buffer 7, the signal that EFT Drive Unit 5 is exported is the drive level signal after inverted logic computing, this drive level signal transfers to the grid of field effect transistor 1, thereby the duty ratio of field effect transistor 1 is changed according to the output signal of pulse-width modulation circuit 8; The output of filter 3 is exported direct current energy through current sampling unit 4, the current sampling signal that current sampling unit 4 is exported carries out after amplification ratio is processed transferring to pulse-width modulation circuit 8 through amplifying comparison circuit 9, the duty ratio of adjusting pulsewidth modulation circuit 8, realizes overcurrent protection function; The direct current of outside input through the first accessory power supply 11 by voltage transformation to pulse-width modulation circuit 8 required voltages, for pulse-width modulation circuit 8 provides work required electric energy, the output of the first accessory power supply 11 inputs to the second accessory power supply 10, by voltage transformation, is and non-buffer 7 required voltages.
The utility model is compared background technology tool and is had the following advantages:
1, the utility model can be realized the rising of output voltage, and rise time that can regulation output voltage, thereby prevents the surge current of starting shooting;
2, the utility model can limit maximum output current, realizes the overcurrent protection of output current, effectively prevents from damaging after electronic equipment short circuit;
3, the utility model adopts logic level control circuit to start, and can realize the Remote of electronic equipment is started.
Embodiment
With reference to Fig. 1, the utility model by field effect transistor 1, inductor 2, filter 3, current sampling unit 4, EFT Drive Unit 5, fly-wheel diode 6, with non-buffer 7, pulse-width modulation circuit 8, amplify comparison circuit 9, the second accessory power supply 10 and the first accessory power supply 11 and form.Fig. 1 is electric functional-block diagram of the present utility model, and embodiment presses Fig. 1 connection line.Rated operational voltage of the present utility model is 28V, and operating voltage range is 18V to 36V, and rated current is 15A, and overcurrent protection electric current is 24 ± 1A, adopts TTL logic level to carry out remote control.
The effect of field effect transistor 1 of the present utility model is the switching device of main circuit, by controlling the conducting duty ratio of field effect transistor 1, and can regulation output voltage swing.Embodiment adopts N NMOS N-channel MOS N field effect transistor, and model is: IRFP064N, manufacturer is American I R company.
The effect of inductor 2 of the present utility model is when cycle field effect transistor 1 is turn-offed, and for load provides electric current, carries out energy storage.Embodiment adopts metal magnetic powder core and enamelled wire coiling to form.
The effect of filter 3 of the present utility model is that output voltage is carried out to filtering.Embodiment adopts aluminium electrolytic capacitor, and model is: CD288H-50V-100 μ F, manufacturer is Jiangxi Lian Sheng Electronics Co., Ltd..
The effect of current sampling unit 4 of the present utility model is that output current is sampled.Embodiment adopts high-accuracy resistor, and model is: BVS-R001-1.0, manufacturer is German Yi Sa company.
The effect of EFT Drive Unit 5 of the present utility model be the pulse signal of exporting with non-buffer 7 is carried out anti-phase, for field effect transistor 1 provides drive level.Embodiment adopts high-speed photoelectric coupler, and model is: HCPL-3180, manufacturer is Agilent technology company.
The effect of fly-wheel diode 6 of the present utility model is being on the scene effect pipe 1 blocking intervals, for main electronic loop provides path, i.e. and afterflow effect.Embodiment adopts Schottky barrier fly-wheel diode, and model is: MBR3045PT, manufacturer is U.S. fairchild company.
The effect of of the present utility model and non-buffer 7 is that the pulse signal that logic control level signal and pulse width modulator 8 are exported carries out NAND Logic computing, realizes the remote control start-up performance of main circuit, and exports operation result to EFT Drive Unit 5.Embodiment adopts 5 inputs four and non-buffer, and model is: SN54LS38J, manufacturer is American TI Company.
The effect of pulse-width modulation circuit 8 of the present utility model is to provide pulse signal for main circuit, adjust pulse duration, the pulse signal of output through with non-buffer 7 and EFT Drive Unit after, control field effect transistor 1 duty ratio, and then realize the control of output voltage, realize the slow function that rises of voltage.Embodiment adopts one group of comparator to produce sawtooth waveforms, and another group comparator compares computing by a DC level signal and sawtooth signal, output pulse model.
The effect of amplification comparison circuit 9 of the present utility model is that the small-signal that current sampling unit 4 is exported amplifies; and signal and a threshold voltage after amplifying are compared; signal after treatment is transferred to pulse-width modulation circuit 8; control impuls duty ratio; and then realize electric current restriction, realize overcurrent protection function.Embodiment adopts composition in-phase amplification circuit, the comparison circuits such as amplifier and peripheral resistor, capacitor.
The effect of the first accessory power supply 11 of the second accessory power supply 10 of the present utility model is that input voltage is converted into suitable voltage value, for the work of each several part provides electric energy.Embodiment adopts linear three terminal regulator, and the model of the second accessory power supply 10 is: CW78L05MT, the model of the first accessory power supply 11 is: CW78M12MK, Liang Zhong three terminal regulator manufacturer is Beijing semiconductor five factories.
Concise and to the point operation principle of the present utility model is as follows:
Field effect transistor 1, inductor 2, filter 3 and fly-wheel diode 6 form basic adjusting and voltage-reduction switch voltage stabilizing circuit, by controlling the duty cycle of switching of field effect transistor 1 by 0 to 100% variation, make output voltage rise to 28V from 0V, realize the slow function that rises of voltage.The pulse signal that pulse-width modulation circuit 8 is exported and TTL logic control level signal are by carrying out after NAND Logic computing with non-buffer 7; export EFT Drive Unit 5 to; pulse signals is carried out anti-phase and current driving ability amplification; for field effect transistor 1 provides drive level; the duty cycle of switching of field effect transistor 1 is changed according to the duty ratio of pulse signal; the sampled signal of current sampling unit 4 is through amplifying after comparison circuit 9 processing; the duty ratio of controlling pulse-width modulation circuit 8 output pulse signals, realizes overcurrent protection.
Concise and to the point mounting structure of the present utility model is as follows:
Each part of the present utility model is all welded in printed board, printed board is fixed in shielding box by the installing hole of four jiaos, field effect transistor 1 and fly-wheel diode 6 are installed on printed board bottom surface, installing hole by printed board and shielding box floor is compressed, make itself and shielding box floor close contact, carry out heat loss through conduction, contact-making surface pad heat conductive insulating pad, and coated with thermally conductive silicone grease, shielding box side plate is provided with 3 connectors, and the input of printed board, output and control terminal are connected to corresponding connector according to corresponding relation by wire.