JPH08205399A - Ac adaptor - Google Patents

Abstract

PURPOSE: To reduce power consumption by detecting the condition of control of the load of a DC generating means on the basis of a specified voltage value set beforehand, and stopping the control of a switching regulator only at the time of no load. CONSTITUTION: A rectified and smoothed AC power source 1 switched by a switching regulator 4 is inputted to the primary winding 51 of a transformer 5, and its secondary winding 52 sends out output voltage. On one side, flyback voltage generated with the tertiary winding 53 of the transformer 5 is rectified and smoothed, and by supplying the voltage the switching regulator 4 is controlled. On the other side, the output voltage of the secondary winding 52 is rectified and smoothed, and supplied to a load. Furthermore, a detecting means 8 which detects this load voltage, collates it with a voltage set beforehand, and learns the condition of connection of the load is provided, and control 31 of stopping the switching 4 only at the time of no load is performed. Consequently, it becomes possible to reduce wasteful power consumption.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an AC adapter,
In particular, it relates to an AC adapter equipped with a power saving means.

[0002]

2. Description of the Related Art As shown in FIG. 2, a conventional AC adapter continues to oscillate and continuously output an output voltage even when the output side is unloaded, unless the input AC power supply is stopped.

The operation of this conventional AC adapter is, as shown in FIG. 2, an input diode Di and an input capacitor C.
When the AC power supply 1 rectified and smoothed by i is input to the primary winding 51 of the transformer 5, the starting capacitor Cs is charged through the input resistance Ri, and the voltage across the starting capacitor Cs is the power supply Vcc of the control IC 31 and The start signal is supplied to the start signal ON / OFF via the start resistor Rs to start the switching regulator 4.

After that, the output voltage generated in the secondary winding 52 of the transformer 5 is rectified and smoothed by the output diode Do and the output capacitor Co, and the smoothed output voltage is biased by the photocoupler PC1t by the resistors R7 and R8. The light emission is detected and emitted via the Zener diode ZD and the resistor R6 which are operated, and the photo-coupler PC1r is operated by this detection and the start control signal FB supplied to the control IC 31 is stopped, and the tertiary winding 53 of the transformer 5 The generated flyback voltage is rectified and smoothed by the starting diode Ds and the starting capacitor Cs to become the power supply voltage of the control IC 31, and the operation of the switching regulator 4 is continued.

[0005]

In the conventional AC adapter, even if the output is unloaded, the output voltage is output and the AC adapter is operating unless the AC power supply is stopped. There was a problem of consuming electric power.

Therefore, an object of the present invention is to provide an AC adapter which reduces the power consumption by stopping the operation when there is no load.

[0007]

In order to solve the above-mentioned problems, an AC adapter of the present invention comprises a rectifying means for rectifying and smoothing an input AC power source, and an AC power source rectified and smoothed by this rectifying means. The switching regulator for switching the switching regulator and the rectified and smoothed AC power source switched by the switching regulator are input to the primary winding to output the output voltage to the secondary winding, and flyback to the tertiary winding. A transformer for generating a voltage, a control means for controlling the switching regulator by supplying a voltage obtained by rectifying and smoothing a flyback voltage generated in a tertiary winding of the transformer, and an output sent to the secondary winding. Detects the connection state of the direct current generating means for rectifying and smoothing the voltage and the load of the direct current generating means based on a predetermined voltage value set in advance. Detection means that, characterized in that it consists of a starting means for stopping only the control means when the load is detected as not connected by the detecting means.

In order to solve the above-mentioned problems, the AC adapter of the present invention is characterized in that it is constituted by the control means for controlling the switching regulator by a control IC.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an AC adapter according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a circuit diagram of an AC adapter according to an embodiment of the present invention.

An AC adapter according to an embodiment of the present invention is
As shown in FIG. 1, a rectifying means 2 for rectifying and smoothing the input AC power source 1 by an input diode Di and an input capacitor Ci, and a switching regulator for switching the AC power source 1 rectified and smoothed by the rectifying means 2 ( SR) 4 and this switching regulator (SR)
Rectified and smoothed AC power supply 1 switched by 4
Generated in the tertiary winding 53 of the transformer 5 and the transformer 5 that outputs the output voltage to the secondary winding 52 and generates the flyback voltage in the tertiary winding 53. DC for rectifying and smoothing the output voltage sent to the secondary winding 52 by the output means Do and the output capacitor Co for controlling the switching regulator 4 by supplying a voltage obtained by rectifying and smoothing the flyback voltage. The generating means 7, the detecting means 8 for detecting the connection state of the load of the direct-current generating means 7 based on the preset voltage value of the battery e, and the detecting means 8 detects that the load is not connected. It comprises a starting means 6 for stopping the control means 3 only when.

The control means 3 includes a control IC 31 controlled by the switching regulator 4 and an input capacitor C.
A starting capacitor Cs that charges the AC power supply 1 smoothed by i through the input resistor Ri and smoothes the flyback voltage, and a starting resistor Rs that supplies the voltage across the starting capacitor Cs to the control IC 31 as a starting signal ON / OFF. , A photocoupler PC1r for supplying a ground signal to the control IC 31 when the AC power supply 1 is input, and a photocoupler PC1t for detecting and emitting the output voltage of the DC generator 7 through the Zener diode ZD biased by the resistors R7 and R8 and the resistor R6. And a starting diode Ds for rectifying the flyback voltage generated in the tertiary winding 53 of the transformer 5.

Further, the detecting means 8 includes diodes D1,
A photocoupler PC2t for detecting the connection state of the load of the DC generating means 7 to the battery e via the resistor R9 based on the voltage value of the battery e connected to the DC generating means 7 via D2.
Composed of and.

On the other hand, the starting means 6 passes through the transistors Q1 and Q2 biased by the resistors R1, R2, R3 and R4 only when the photocoupler PC2t of the detecting means 8 detects that the load is not connected. , And a photocoupler PC2r for controlling the control IC 31 to send an activation signal OFF via the resistor R5.

Next, the operation of the AC adapter according to the embodiment of the present invention will be described with reference to the drawings.

As shown in FIG. 1, the operation of the AC adapter according to the embodiment of the present invention detects when the DC generator 7 has a load (load state: a state in which a load device is connected to the output side). Based on the battery e through the diode D2 of the means 8, the photocoupler PC2t emits light through the diode D1 and the resistor R9, the photocoupler PC2t emits light, and the photocoupler PC2r of the starting means 6 is turned on, The transistor Q2 is turned on and the transistor Q1 is turned off via the resistor R5, and the activation signal of the control IC 31 is turned on /
OFF becomes ON state (HIGH level).

On the other hand, when the DC generator 7 has no load (no load condition: no load device is connected to the output side), the photocoupler PC2t of the detector 8 does not emit light, and the photocoupler of the starter 6 is not illuminated. PC2r is turned off, transistor Q2 is also turned off, and transistor Q2
1 becomes the ON state and the start signal ON / O of the control IC 31
FF becomes OFF state (LOW level), and control IC3
1 stops oscillating and the AC adapter stops operating.

Alternatively, when the unloaded state is changed to the loaded state, the diode D1 is detected based on the battery e of the detecting means 8.
And the photocoupler PC2t is emitted through the resistor R9, the photocoupler PC2r of the starting means 6 is turned on,
The transistor Q2 is turned on through the resistor R5, the transistor Q1 is turned off, and the start signal of the control IC 31 is turned on /
OFF turns to ON state (HIGH level) and control IC
31 starts oscillating to start the operation of the AC adapter, and the light emission of the photocoupler PC2t is stopped from the time when the output voltage rises due to the start of the operation of the AC adapter.

[0019]

As described above, according to the AC adapter of the present invention, when the connection state of the load on the output side is detected and the load is not connected to the output side, the operation is stopped, so that there is no waste. This has the effect of reducing unnecessary power consumption.

[Brief description of drawings]

FIG. 1 is a circuit diagram of an AC adapter according to an embodiment of the present invention.

FIG. 2 is a circuit diagram of a conventional AC adapter.

[Explanation of symbols]

 1 AC power supply 2 Rectifying means 3 Control means 4 Switching regulator 5 Transformer 6 Starting means 7 DC generating means 8 Detecting means 31 Control IC 51 Primary winding 52 Secondary winding 53 Third winding Ci Input capacitor Co Output capacitor Cs Starting Capacitor D1, D2 diode Di input diode Do output diode Ds start diode e battery Q1, Q2 transistors R1 to R9 resistance Ri input resistance Rs start resistance ZD Zener diode

Claims (2)

[Claims] 1. A rectifying unit that rectifies and smoothes an input AC power source, a switching regulator that switches the AC power source that is rectified and smoothed by this rectifying unit, and the rectifying and smoothing unit that is switched by this switching regulator. A transformer that inputs an AC power supply to the primary winding, sends out an output voltage to the secondary winding, and generates a flyback voltage on the tertiary winding, and a flyback generated by the tertiary winding of this transformer. Control means for controlling the switching regulator by supplying a voltage obtained by rectifying and smoothing the voltage, direct current generating means for rectifying and smoothing the output voltage sent to the secondary winding, and a connection state of a load of the direct current generating means. Is detected based on a predetermined voltage value set in advance, and when the detection means detects that the load is not connected, An AC adapter comprising a starting means for stopping the control means. 2. The AC adapter according to claim 1, wherein the AC adapter comprises the control means for controlling the switching regulator by a control IC.