JP2009219218A - Switching apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce input power at no load, and to shorten the rise time of output voltage. <P>SOLUTION: The switching apparatus is comprised of: a bridge rectifier diode and a smoothing capacitor that rectify and smooth AC power input; a switching element for controlling secondary output; a switching controlling means that controls the turn-on/off of the switching element; and a switching transformer having primary winding one end of which is connected to the positive pole of the smoothing capacitor and the other end of which is connected to the switching element, auxiliary winding connected to the switching controlling means, and secondary winding that does output on the secondary side. A capacitor is connected in parallel with a starting resistor connected between the positive pole of the smoothing capacitor and the control terminal of the switching element. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a switching power supply device for charging a portable device.

  In recent years, switching power supply devices that are AC-DC converters equipped with self-excited ringing choke converter circuits reduce input power consumption (hereinafter referred to as standby power) when there is no output load, so there is no output load. In many cases, low standby power is achieved by setting peripheral component constants of the switching element so that switching is intermittently oscillated at the time of load. Hereinafter, the above-described switching circuit configuration will be described with reference to the drawings. In FIG. 2, 1 is an AC power source, 2 and 3 are bridge rectifier diodes and smoothing capacitors for rectifying and smoothing the AC power input, and 4 is a switching transformer having a primary side winding, a secondary side winding, and an auxiliary winding. is doing. 5 is a switching element, 6 is an output current rectifier diode, 7 is an output smoothing electrolytic capacitor, 8 is an output current detection resistor, 9 is output current detection means, 10 is output voltage detection means, 11 is output transmission means, and 12 is switching control. Means, 13 is a sub-transistor, 14 is a switching stabilization diode, 15 is an output current, 16 is an output voltage, and 17 is a ceramic capacitor for switching stabilization. The control method of the output current and the output voltage of the switching power supply device is such that the AC input voltage supplied from the AC power supply 1 is converted into a DC power supply by the bridge rectifier diode 2 and the smoothing capacitor 3, and the DC power supply is switched by the switching element 5. By converting the pulse and supplying it to the switching transformer 4, it is output to the output side circuit unit, and the output current 15 and the output voltage 16 of the switching power supply device are detected by the output current detecting means 9 and the output voltage detecting means 10, and the detection is performed. By controlling the switching control means by outputting the result output to the output transmission means 11 and performing the switching control of the switching element 5, the output of the output current 15 and the output voltage 16 of the switching power supply device is controlled to be stable. Ceramic capacitor for switching stabilization of output side circuit No-load no output load by adjusting the capacity of the sub 17 is switching of the switching element 5 is performing a reduction of standby power becomes intermittent oscillation.

Also, some terminals connected to switching power supply devices recently have a function that does not operate the terminal if the time until the output voltage of the switching power supply rises to the rated voltage (hereinafter referred to as the output voltage start-up time) is slow. Some devices have low standby power and a high output voltage startup time.
JP 2001-320878 A JP 2003-92877 A

  However, in order to reduce standby power, the most effective means is to set constants for the peripheral components of the switching element, in particular by increasing the resistance value of the starting resistor connected between the positive electrode of the smoothing capacitor and the control terminal of the switching element. There is a method of reducing the power loss. However, if the resistance value of the starting resistor is increased, the time until the switching element is turned on after the AC power is input becomes longer, and the switching element is completely stopped from oscillating until the switching element is turned on. Is not supplied with power, and the startup time of the output voltage is delayed. Conversely, shortening the start-up time of the output voltage is possible by reducing the resistance value of the start-up resistor, but standby power increases, and the current circuit configuration reduces the input power at no load. That is, it is difficult to achieve both low standby power and high output voltage startup time.

  The present invention solves the above-described problem, and controls a bridge rectifier diode and a smoothing capacitor for rectifying or smoothing an AC power input, a switching element for controlling a secondary side output, and controlling on / off of the switching element. Switching control means, and at least one is connected to the positive electrode of the smoothing capacitor, the other is connected to the switching element, the primary winding connected to the switching control means, the auxiliary winding connected to the switching control means, and the output to the secondary side A switching device including a switching transformer having a secondary winding, wherein the capacitor is connected in parallel to a starting resistor connected between the positive electrode of the smoothing capacitor and the control terminal of the switching element.

  The present invention enables low standby power and faster output voltage startup time.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

(Embodiment 1)
In FIG. 1, 1 is an AC power source, 2 and 3 are bridge rectifier diodes and smoothing capacitors for rectifying and smoothing the AC power input, and 4 is a switching transformer having a primary side winding, a secondary side winding, and an auxiliary winding. is doing. 5 is a switching element, 6 and 7 are rectifier diodes and smoothing electrolytic capacitors for rectifying and smoothing the secondary winding voltage of the switching transformer 4, 8 is a resistor for detecting an output current, and 9 and 10 are output currents, respectively. The output transmission means 11 is means for detecting the output voltage, and means for transmitting the output signals 9 and 10 to the primary side. Reference numeral 12 denotes switching control means for controlling the switching of the switching element 5 by a signal from the output transmission means 11, and reference numerals 13 and 14 denote subtransistors and switching stabilization diodes in the circuit of the switching control means. 15 is an output current, 16 is an output voltage, 17 is a ceramic capacitor for stabilizing switching, 18 and 19 are first starting resistors and second starting resistors, respectively, and 20 is a capacitor for speeding up the output voltage starting time. 18 or the second starting resistor 19 is connected in parallel. The AC adapter output current and output voltage are controlled by converting the AC input voltage supplied from the AC power source 1 into a DC power source by the bridge rectifier diode 2 and the smoothing capacitor 3, and pulsing the DC power source by switching the main transistor 5. By converting it and supplying it to the switching transformer 4, it outputs to the secondary side output circuit section, and the output current 15 and output voltage 16 of the AC adapter are detected by the output current detection means 9 and the output voltage detection means 10, and the detection The signals of the means 9 and 10 are transmitted to the primary side by the output transmission means 11, and the sub-transistor 13 is controlled to control the switching of the main transistor 5. As a result, the output current 15 and output voltage 16 of the AC adapter are controlled.

  When there is no output load, the stand-by power when there is no output load is obtained by optimizing the component constants in the switching control means 12 and increasing the resistance values of the first and second starting resistors 18 and 19. Switching control of the main transistor 5 is performed so as to be small (for example, 10 mW or less). By connecting a capacitor 20 in parallel to the first starting resistor 18 (or the second starting resistor 19), the current for turning on the switching element 5 immediately after the AC power supply 1 is input is the starting resistor 18 (or 19). Instead, the current flows through the capacitor 20, and this current has a larger current value than that when the current flows through the starting resistor. Therefore, the turn-on time of the switching element 5 is accelerated and the power supply to the secondary output circuit section is also accelerated. The startup time of the output voltage can be shortened. When the capacitor is charged, the current flows through the starting resistors 18 and 19 instead of the capacitor, and the switching element 5 is turned on. By connecting the capacitors in this way, it is not necessary to reduce the starting resistance in order to increase the output voltage start-up time, and it is possible to reduce the standby power and speed up the output voltage start-up time.

Comparison of standby time and start-up time of the output voltage in the circuit of the embodiment of the present invention (FIG. 1) and the conventional circuit (FIG. 3) was performed under the following conditions.
[conditions]
(1) The test uses a mobile phone AC adapter.

  (2) In the conventional circuit, there are two ways of implementation, when the resistance value of the starting resistor is increased and when the resistance value of the starting resistor is decreased.

  The comparison results are shown below.

  As shown in the above result, when the starting resistance is large in the conventional circuit, the standby power is low, but the starting time of the output voltage is delayed compared to the embodiment of the present invention. In addition, when the starting resistance is small, it can be seen that the starting time is earlier, but the standby power is increasing. On the other hand, in the embodiment of the present invention, the standby power is low and the startup time of the output power is quick, so that the effectiveness of the present invention can be seen.

  As described above, the present invention is a switching device that can reduce the input power consumption when there is no output load, that is, achieve both low standby power and faster startup time of the output voltage.

1 is a basic circuit diagram of a switching device shown in Embodiment 1 of the present invention. Basic circuit diagram of switching device shown in embodiment 2 of the present invention Basic circuit diagram of conventional switching device

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 AC power supply 2 Bridge rectifier diode 3 Smoothing capacitor 4 Switching transformer 5 Switching element 6 Output current rectifier diode 7 Output smoothing electrolytic capacitor 8 Output current detection resistor 9 Output current detection means 10 Output voltage detection means 11 Output transmission means 12 Switching control means 13 Subtransistor 14 Switching stabilization diode 15 Output current 16 Output voltage 17 Switching stabilization ceramic capacitor 18 First starting resistor 19 Second starting resistor 20 Capacitor

Claims (3)

Bridge rectifier diode and smoothing capacitor for rectifying or smoothing AC power input, switching element for controlling secondary output, switching control means for controlling on / off of switching element, at least one of which is positive electrode of smoothing capacitor And a switching transformer having a primary winding connected to the switching element, an auxiliary winding connected to the switching control means, and a secondary winding that outputs to the secondary side. In
A switching device comprising a capacitor connected in parallel to a starting resistor connected between a positive electrode of a smoothing capacitor and a control terminal of a switching element. A bridge rectifier diode and a smoothing capacitor for rectifying or smoothing the AC power input, a switching element for controlling the output on the secondary side, a switching control means for controlling on / off of the switching element, and at least one of which is a smoothing capacitor The switching transformer comprising a primary winding connected to the positive electrode and the other connected to the switching element, an auxiliary winding connected to the switching control means, and a secondary winding that outputs to the secondary side. In the device
By reducing the input power consumption when there is no load by the resistance value of the starting resistor connected between the positive electrode of the smoothing capacitor and the control terminal of the switching element, and connecting the capacitor in parallel to the starting resistor, AC 2. The switching device according to claim 1, wherein the start-up time of the secondary side output voltage immediately after the power input is shortened. Bridge rectifier diode and smoothing capacitor for rectifying and smoothing AC power input, switching element for controlling secondary output, switching control means for controlling on / off of said switching element, at least one of which is positive electrode of smoothing capacitor And a switching transformer having a primary winding connected to the switching element, an auxiliary winding connected to the switching control means, and a secondary winding that outputs to the secondary side. In
The first starting resistor and the second starting resistor connected between the positive electrode of the smoothing capacitor and the control terminal of the switching element reduce input power consumption when there is no load, and the first starting resistor or the second starting resistor 2. The switching device according to claim 1, wherein the start-up time of the secondary output voltage immediately after the AC power supply is input is shortened by connecting a capacitor in parallel to one of the start resistors.

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