Design content: DC series regulated power supply
A series DC stabilized power supply with adjustable output voltage of 6~ 15V is designed, which converts the commercial power (220V/50HZ alternating current) into 6~ 15V DC stabilized voltage through power transformer, rectifier circuit, filter circuit and stabilized voltage circuit.
catalogue
1. Design requirements
Secondly, describe the principle of DC regulated power supply.
3. Design Steps and Selection of Circuit Components
Four: the circuit diagram of each module and its simulation results.
Verb (abbreviation of verb) general circuit diagram and its simulation results.
Six: Summary
1. Design requirements
A series regulated DC power supply with a maximum load current of about1000 mA and an adjustable output voltage of 6~ 15V is designed. The commercial power (220V/50HZ alternating current) is converted into a stable DC voltage of 6~ 15V through a power transformer, a rectifier circuit, a filter circuit and a regulated circuit.
Secondly, describe the principle of DC regulated power supply.
Electronic equipment generally needs DC power supply. Except for a few direct-use dry batteries and DC generators, most of these DC power supplies are DC stabilized power supplies, which convert alternating current (commercial power) into direct current.
Figure (1) Block diagram of DC regulated power supply
Figure (4) Series Regulator with Amplifier
Figure (5) Circuit diagram of 5)DC series regulated power supply
DC regulated power supply consists of four parts: power transformer, rectifier, filter and regulated circuit. Its principle block diagram is shown in figure (1). The AC voltage U 1(220V, 50Hz) provided by the power grid is reduced by the power transformer to obtain the AC voltage U2 that meets the needs of the circuit, and then it is converted into the pulsating voltage U3 with constant direction and time-varying amplitude by the rectifier circuit, and then its AC component is filtered out by the filter, so that a relatively flat DC voltage UI can be obtained. However, this DC output voltage will also change with the fluctuation of AC grid voltage or load. In the occasion of high demand for DC power supply, it is also necessary to use a voltage stabilizing circuit to ensure a more stable DC voltage output.
Figures (2), (3) and (4) are connected in series to form the circuit diagram of the series regulated power supply with amplification link, that is, Figure (5), and the rectification part is a single-phase bridge rectifier and a capacitor filter circuit. The voltage stabilizing part is a series voltage stabilizing circuit with an amplifier, which is composed of regulating elements (composite tube composed of transistors Q 1 and Q2). Comparative amplifier (integrated operational amplifier a); Sampling circuits R2, R4, R3, reference voltage DZ, R 1, etc. The whole voltage stabilizing circuit is a closed-loop system with voltage series negative feedback. The voltage stabilizing process is as follows: when the output DC voltage changes due to the fluctuation of power grid voltage or load, the sampling circuit takes out a part of the output voltage and sends it to the comparison amplifier for comparison with the reference voltage. The generated error signal is amplified by the comparison amplifier and sent to the base of the regulator tube, so that the regulator tube changes its tube voltage drop to compensate for the change of output voltage, thus achieving the purpose of stabilizing the output voltage.
3. Design Steps and Selection of Circuit Components
The design process is modular. Firstly, the circuits of each module are designed in turn, and the simulation is correct, and then they are connected in series to form the overall circuit diagram.
Circuit component selection:
1:determination of ui
Ui=Uo+Uce, because uomax = 15v, Uce >；; Uces= 1~2V, take Uces=2V, so ui = uomax+uces =17v;
2. Selection of regulating tube
UC emax = UI-uo min = 17-6 = 1 1V。 In order to expand the output current range, a composite pipe composed of D42C8 and D42C3 is adopted.
3. Selection of Zener diode Dz
Uz is less than or equal to Uomin=6V, in which ZPD5. 1 regulator is selected, with parameters Uz = 5. 18V and Iz =1~10ma;
4. Selection of resistance R 1
Ur1= ui-uz =17-5 =12v, IR 1 take 10ma, r1= ur1/IR/kloc.
5. Selection of integrated operational amplifier
Because the circuit has low requirements for integrated operational amplifier, a general integrated operational amplifier is selected.
6. Selection of filter capacitor C 1
In order to improve the filtering effect, C 1 selects 470uf electrolytic capacitor;
7. Determination of resistors R2, R3 and R4 in sampling process
Uomax=(R2+R3+R4)*Uz/R3
Uomin=(R2+R3+R4)*Uz/(R3+R4)
Where R4 is a sliding rheostat with the maximum resistance of 1Ko, Uz = 5. 18V, UOMAX = 15V, UOMIN = 6V, and simultaneous equations can be obtained, with R2=264ohm and R3 = 666ohm.
8.8: Determination of U2 and Transformer
Full-wave rectifier circuit, Ui= 1.2U2, so U2=Ui/ 1.2= 14V, select the transformer with the transformation ratio of 10: 1, and get the voltage of 14V after resistance division;
9. The choice of rectifier diode
Urm>1.1*1.414 * U2 =1.1.414 *14 = 20
Four: the circuit diagram of each part and its simulation results.
1 Circuit diagram of power transformer and its simulation results
The power transformer converts the AC power supply voltage (220V/50HZ) into an appropriate AC voltage u2.
Circuit diagram of single-phase bridge rectifier and its simulation results
The task of rectifier circuit is to convert AC voltage into DC pulsating voltage.
Circuit diagram:
Simulation results:
Circuit diagram of capacitor filter and its simulation results
Circuit diagram:
Simulation results: the filter capacitance C=22uf.
When the filter capacitance C=470uf.
Circuit diagram of series voltage stabilization with amplifier and its simulation results
Verb (abbreviation of verb) general circuit diagram and its simulation results.
By adjusting the resistance of sliding rheostat R4, a stable DC voltage of 6~ 15V can be obtained.
Simulation results:
Waveform diagram of input voltage U2
Waveform diagram of output voltage U0
Summary and experience of curriculum design of intransitive verbs
1 Through the design of this regulated power supply, I consolidated and deepened the theoretical knowledge I learned in the course of analog electronic technology, got a deeper understanding of rectifier circuit, filter circuit and regulated circuit, learned to consult relevant manuals and materials, and improved my ability to analyze and solve problems.
2 The design sequence of modules can optimize the design process and make it more logical. However, it should be noted that every link must be carried out seriously. A bad or wrong design of a module circuit will inevitably affect the whole circuit, so we should keep a serious and rigorous attitude in the design process;
This course design is a process of integrating theory with practice, and many practical problems will be encountered in the design. Theoretically correct results may have various unexpected results in the simulation, which requires us to proceed from reality and consider the actual situation as much as possible in the design process. In addition, when encountering problems, we should learn to combine theory with practice to analyze and solve problems;
Through this course design, I have basically mastered the use of the design software Multisim200 1 and mastered the design method of electronic circuits, which requires more practice and proficiency in the future.
Looking back on this course design, I have a lot of feelings so far. From topic selection to finalization, from theory to practice, I understand the importance of combining theory with practice. Theoretical knowledge is not enough. Only by combining theoretical knowledge with practice and drawing conclusions from theory can we truly master knowledge, thus improving our practical ability and independent thinking ability.