KR20020095008A - A voltage transformer with diode and condenser - Google Patents

Abstract

PURPOSE: A voltage transformer using a diode and a condenser is provided to boost or lower each voltage according to each circuit by using the condenser instead of a coil and determining output voltages by using a diode. CONSTITUTION: The charge current flows in an order of the first switch(S1), the first condenser(C1), the second diode(D2), the second condenser(C2), the fifth diode(D5), and the third condenser(C3) if the first switch(S1) is turned on. At this time, 1/3 of input voltage is charged into each condenser if the condensers have the same capacity without considering forward voltage. The positive charges of the first condenser(C1) are charged into the fourth condenser(C4) through the second switch(S2) and the negative charges of the first condenser(C1) are charged into the fourth condenser(C4) through first diode(D1) if the first switch(S1) is turned off and the second switch(S2) is turned on. The positive charges of the second condenser(C2) are charged into the fourth condenser(C4) through the third condenser(C3) and the second switch(S2) and the negative charges of the second condenser(C2) are charged into the fourth condenser(C4) through the fourth diode(D4). The positive charges of the third condenser(C3) are charged into the fourth condenser(C4) through sixth diode(D6) and the second condenser(C2) and the negative charges of the third condenser(C3) are charged into the fourth condenser(C).

Description

Voltage converter with diode and condenser {A voltage transformer with diode and condenser}

The present invention relates to a technique for lowering or raising the voltage in a power supply or a circuit to match a used device or a circuit. Currently, coil type transformer or switching power supply technology is widely used for this purpose. Coil type is easy to design but heavy, and switching type is light but circuit design and fabrication is relatively easy. In addition, a method of using the voltage dividing characteristic when the capacitors are connected in series has been introduced, but in this case, the capacity of the capacitors must be exactly the same and the secular variation must be the same so that the same voltage is not easy.

In order to solve this disadvantage, the present invention uses a capacitor instead of a coil, but only for charge accumulation, and the output voltage can be determined by a diode circuit, and in order to prevent too many capacitors or diodes, We want to construct a multiplication system between stages. To do this, a separate control circuit that can generate a control waveform must be added. Here, it is possible to simply use a power wave or connect a separate oscillator, and increase the oscillation frequency in case of high current demand. It is possible to make it adjustable or to make automatic adjustment with a voltage proportional oscillator (VCO) and to provide an overvoltage protection circuit against the breakdown of the switching element.

1 is a basic circuit diagram of the present invention (a) step-down device, (b) step-up device

2A is a circuit diagram for explaining a function of dividing equally regardless of capacity

2b is a capacitor voltage change diagram for explaining the above function

3A is a circuit diagram with the addition of a VCO

3B is a circuit diagram of a semi-fixed oscillator, overvoltage protection, and a linear constant voltage circuit.

Figure 3c is a circuit diagram with a VCO and a two-stage transformation

Figure 4a is a step-down circuit diagram using a commercial power source as a drive source (single configuration)

Figure 4b is a step-down circuit diagram using a commercial power source as a drive source (multi-stage configuration)

4C is a step-down circuit diagram using commercial power as a driving source (onion output)

Figure 5a is a step-down circuit using a commercial power source as a drive source (using a power FET, half-wave output)

5b is a step-down circuit using a commercial power source as a driving source (using a power FET, onion output)

Figure 5c is a step-down circuit using a commercial power source as a drive source (using a power FET, AC output)

6 is a boost circuit diagram using a commercial power source as a drive source

7A is a circuit diagram of a boost / step-down circuit module.

7B is an optical switching drive circuit diagram using an AC power source

7C is an optical switching drive circuit diagram using a self-oscillator

The present invention merely utilizes that the output is divided into partial pressure when the series or parallel connection state of the battery or charged capacitor is changed in series-> parallel and back-pressure when it is changed in parallel-> serial. It is designed to be done automatically using diodes and switching elements. 1 (a) shows the step-down base circuit, (b) shows the configuration of the step-up base circuit.

In FIG. 1A, when S1 is turned ON, the charging current flows from S1-> C1-> D2-> C2-> D5-> C3. At this time, each capacitor has the same capacity and ignores the forward voltage of the diode. In each case, 1/3 of the input voltage is charged. Then, when S1 turns off and S2 turns on, the positive charge of C1 is charged to C4 via S2, and the negative charge is charged to C4 via D1. The positive charge of C2 is D3-> S2-> C4, the negative charge is D4-> C4, and the positive charge of C3 is charged D6-> S2-> C4, the negative charge is immediately charged to C4, where C4 is the voltage of C1, C2, C3 Separately or in parallel, approximately one third of the supply voltage is charged, and the above switching is repeated to achieve a complete third to achieve the step-down function.

In FIG. 1 (b), when S1 is turned on, the input current is charged in parallel to D1-> C1-> D2, D3-> C2-> D4, D5-> C3-> D6, and the voltage of each of C1, C2, and C3 is powered. Equal to voltage. After S1 is off and S21 and S22 are on, C3-> S22-> C2-> S21-> C1 is connected in series, and about 3 times of the power voltage is charged to C4, and when it is repeated, it is completely 3 times Boosting function is achieved.

However, even if the same capacitor is used, the capacity may be uneven or deteriorated. In this case, the step-up circuit is not a problem, but in the step-down circuit is a considerable problem, because the voltage outside the equal voltage is charged and discharged to the individual capacitor. 2A and 2B are intended to show that the circuit according to the present invention can solve this problem, and deliberately set C1 = 10uF and C2 = 90uF. In FIG. 2A, when S1 is closed and charged, 90 V is formed at C1 and 10 V is formed at C2. Opening S1 and closing S2 will charge C3 with a voltage lower than 10V. This is the same as usual, but the situation is different if you repeatedly turn on and off S1 and S2 alternately. If C3 is large enough, then the Vout voltage will be constant at 50V, exactly 1/2 of the input. FIG. 2B illustrates the progress of this process. First, since 90V charged in C1 becomes a relatively high voltage from the moment S1 is turned off, C2 prevents C2 from discharging through D4. Therefore, even when S2 is conducted, the charge of C2 is almost preserved and only C1 is discharged, and when C3 is larger and lowers than the voltage of C2, C2 also discharges slightly. After that, when S2 turns off and S1 turns on and is newly charged, C2 is also newly charged due to the high discharge of C1, so the voltage across C2 is increased. At this time, the voltage charged to C2 is higher than the voltage 10V previously charged to C2, but C1 is charged to a voltage lower than the previous voltage of 90V. The proof of this is as follows.

In FIG. 2A, when the output smoothing capacitor C3 is sufficiently large, C1, C2 charged by the input voltage Vi becomes the same voltage Va for each of the voltages V1, V2, V3 of C1, C2, C3 after discharge by S2. After that, when the new charge is calculated, the increase and decrease sign of the voltage charged to V1 and V2

Because of

Therefore, the voltage V1 of the small capacitor C1 gradually decreases, and the voltage V2 of the large capacitor gradually increases, so that both later become 1/2 Vi as shown in FIG. 2B. The capacity of the output smoothing capacitor C3 used at this time can be prevented from stopping when V2 or V3 is high when the smoothed voltage V3 is less than V2. : Vi, Cn voltage between both ends: Vn, output voltage: Vo)

Should be V2> V3

∴ C3> C2-C1

That is, C3 is satisfied if it is equal to or larger than the capacitance difference between C1 and C2, and C1 = C2 or if a proper load resistance is always applied, but it is preferable to be smooth. If the capacitor capacity is set incorrectly as in the case of 2 series, what happens if it is 3 series instead of 2 series, then investigate whether the lower voltage increases to 1/3 when repeated charging and discharging.

If C1, C2, C3 is configured as shown in Fig. 1, and its capacity is C1 <C2 <C3 and the output smoothing capacitor C4 is sufficiently large, the voltages of C1, C2, C3, C4 after discharge by S2 are all the same voltage Va. After that, when the new charge is calculated, the increase and decrease sign of the voltage charged to V1 and V3 is calculated.

, Because of

That is, the smaller the capacity, the higher voltage V1 will gradually decrease, and the larger the capacity, the lower voltage, V3, will gradually increase to one third of the input voltage. In addition, the minimum capacity of the output smoothing capacitor C4 required to achieve this is obtained as follows.

,

Should be V3> V4

4 C4> C3-C1

Therefore, it can be seen that the capacity of the output smoothing capacitor C4 is equal to or greater than the maximum-minimum value of the capacitors participating in the series. It can be inferred that this is the same as in the case of 4 series and 5 series.

FIG. 3A illustrates the converter main circuit of FIG. 1 applied to a conventional switching power supply circuit (SMPS). For the sake of convenience, only the step-down circuit is shown. However, the boost circuit may be connected to S1 at the OUT terminal of the VCO and S21 and S22 at the -OUT terminal. In the circuit of FIG. 3A, the output voltage is sensed by the VCO to increase the pulse output frequency when the voltage is low and vice versa to adjust the number of charge / discharge cycles through the switching element. In the conventional switching power supply, the voltage continues to increase as the duty ratio or frequency increases, but the device according to the present invention utilizes the voltage divider or the back pressure characteristic of the capacitor, so that no matter how high the frequency, the voltage is higher than the voltage due to the step-down ratio or the boost ratio. It is characterized by not being high. Therefore, as long as the switching element allows, high frequency charging and discharging can be performed unconditionally, so control is very easy. Therefore, in FIG. 3b, a method of adopting a fixed pulse oscillator other than VCO and grasping the required current amount at the beginning of use is used to determine the use frequency with a semi-fixed resistor. In addition, overvoltage protection circuits ZD1 and Q5 and linear constant voltage circuits ZD2 and Q6 were added.

The disadvantage of the apparatus according to the present invention is that the number of capacitors to be used increases when the conversion ratio is high. In order to solve this problem, a multistage configuration is taken in FIG. In the figure, for convenience, the number is reduced to 1/2 * 1/3 = 1/6, but if the first stage is 3 times, the second stage is 4 times, and the third stage is 5 times, the condenser 3 + 4 + 5 = 12 is 3 * 4 * 5 = 60 times magnification.

4A illustrates a circuit example using a commercial AC power source as a driving source of the step-up / down circuit switching element. Referring to FIG. 4A, when the AC power applied through the diodes D1 and D5 is + half-wave, D1-> C1. Charging occurs through D3-> C2-> D5. If the series capacitors C1 and C2 have the same capacity, they are charged at half the maximum input voltage. At this time, the reverse bias is applied between the emitter bases of Q1 and Q2. Then, when the half-wave becomes D1, D3, D5 is blocked and Q1, Q2 is forward-biased by the half-wave, so the charge charged in C1 is C1-> Q1-> C3-> Q2-> D2-> C1 The charges charged at C2 are discharged in the paths C2-> D4-> Q1-> C3-> Q2-> C2. At this time, since the power supply voltage is cut off by D1 and D5, naturally only the capacitor voltage is detected. If the cycle of the alternating wave is repeated several times, the voltage of the output smoothing capacitor will appear half the input maximum. Two switching elements are used for isolation between input and output. Figure 4b is a multi-stage connection of this basic circuit constituted a circuit that can be output 1/3 / 1/3 = 1/9 times, and R3, R4 are connected in reverse to alternate charge and discharge. 4c shows a case where the output voltage is obtained in both the + half wave and the-half wave like the onion rectification circuit in the power step-down circuit, and the voltage ripple is greatly reduced, and the insulation between the input and the output is not important. Transistors Q1 and Q2 were used. R3 is a bias current path of Q1 or Q2, and C9, C10 and C11 are fast response capacitors.

5A also uses a commercial power source for driving, but an example of using a power FET (POWER MOSFET) as an output switching device, and only one wire was processed by reducing the insulation between the input and output. In addition, since there is no smoothing capacitor, the output waveform becomes a pulse pulse with the maximum voltage divided by it to be used as the basic unit circuit of the following figure. In FIG. 5B, two sets of FIG. 5A are made, the inputs are connected to lines at different positions, and the outputs are connected to each other at the same positions, so that the onion is rectified as shown in FIG. 4C. In FIG. 5C, two sets are also used. By connecting the output lines in reverse, an AC pulse waveform is obtained, and although it is not a sine wave, AC input-> transformation-> AC output method is realized as if a coil type transformer is used.

FIG. 6 applies such a commercial power supply to a booster circuit. In FIG. 1B, the switch S1 is omitted, and S21 and S22 are replaced by switching transistors (BJTs). If only a protection circuit is added, it is naturally used as a FET or an IGBT. It is possible and the application in two suits is similar.

The characteristic of the circuit utilizing the AC characteristics of the commercial power source can omit the switching semiconductor element corresponding to the input switch switch S1 shown in the basic circuit of FIG. Naturally, the circuit is very simple.

Fig. 7A is modularized with a boost / step-down circuit, so that if the input / output is switched, the boost / step-down ratio is reversed. When the switch S1 is on and off, S21, S22 and S3 are connected to the switch driving circuit so as to be a pair and vice versa. The boosted condition is when the A and B terminals are input C and D terminals as outputs, and when S1 is on and S21, S22 and S3 are off, they are charged in parallel to C1, C2 and C3, and then S1 is off, S21, S22, When S3 is turned on, C1, C2, and C3 are boosted in series and output. Turn the module 180 degrees so that D and C are in the A and B terminals, respectively, D and C are input, B and A are output, and S1 is off and S21, S22 and S3 are on. The C1, C2, and C3 are charged in series, and then S1 is turned on, S21, S22, and S3 are turned off, and C1, C2, and C3 are stepped down in parallel and outputted to the B and A terminals. Such a dual circuit further requires that the switching driver is insulated from the switching element. FIG. 7B uses an optical switching element for controlling the switching element on / off in the module by using an AC power source for driving the LED. FIG. 7C shows a LED being turned on and off by a pulse oscillation circuit operated by an external or module input power source to drive a switching element of the module. In addition, the oscillation frequency can be adjusted so that the power supply may be increased or the capacitor capacity may be smaller at high frequency.

Voltage conversion device according to an embodiment of the present invention is not only a simple conversion of the signal level, such as a conventional double voltage circuit, but also a conversion that can be used as a power is made, so when used in the power supply unit is a small and low loss power supply circuit on the circuit board It can be configured, has advantages in volume, weight, etc., and can eliminate the inconvenience of having to carry a power adapter together with small appliances, and there is no use of coils such as in switching power supply. Will also reduce the burden. Using this module for DC voltage conversion will also provide the DC power supply with the convenience of stepping up and down an AC voltage using a coiled transformer.

Claims (5)

In a voltage converter using a capacitor Through the series-connected diodes [Fig. 1 (a) D1-D2-D3, D4-D5-D6] and the center diodes (D2, D5), several capacitors [Fig. 1 (c) C1, C2, C3] a voltage converter comprising a structure in series connection. In a voltage converter using a capacitor By using the diode-capacitor-diode [Fig. 1 (b) D1-C1-D2] as a pair, another group [Fig. 1 (b) D3-C2-D4, D5-C3-D6] as much as necessary voltage switching element is used. Voltage conversion device characterized in that the structure is coupled through the (1) S21, S22] In the voltage conversion device using the device of claim 1 or 2 With switching elements [Fig. 1 (a) S1, 1 (b) S1] for input and switching elements [Fig. 1 (a) S2, 1 (b) S21, S22] for output. Voltage conversion device characterized by having an oscillation circuit (Fig. 1 (i) OSC, Fig. 1 (b) OSC) for driving this. The method of claim 3 Voltage conversion device for driving the output switching device (Fig. 4a Q1 Q2, Fig. 5a Q1, Fig. 6 Q1 Q2) by using the AC characteristics of the power supply without the input switching device and the oscillation circuit In the voltage converter using the apparatus of claim 2 With an input switching element (Fig. 7A S1) Another separate I / O switching element (FIG. 7A S3) is provided to control the same as the I / O coupling switching element (FIG. 7 S21, S22). Thus, when changing the input / output terminals (Fig. 7 A B, C D), the voltage converter includes a step-up / step-down function in which step-up or step-down are step-up.