CN203800826U - Power supply device with variable switching frequency - Google Patents

Abstract

A power supply device with variable switching frequency comprises a main transformer, a voltage detection unit, a pulse width modulation control unit and a switch unit; the voltage detection unit is electrically connected to the main transformer; the pulse width modulation control unit is electrically connected to the voltage detection unit; the switch unit is electrically connected to the PWM control unit and the main transformer. According to a switching frequency of the switching unit, the main transformer converts an input voltage into an output voltage; the voltage detection unit detects the input voltage and informs the pulse width modulation control unit; according to a voltage absolute value of the input voltage, the PWM control unit controls the switching frequency of the switch unit.

Description

Power Supply Unit with Variable Switching Frequency

technical field

The utility model relates to a power supply device, in particular to a power supply device with variable switching frequency.

Background technique

A power supply device is a very common electronic device; the power supply device provides power to an external electronic device to drive the external electronic device; therefore, the power supply device is very important.

The pulse width modulation controller of the power supply device in the related art controls the transistor switch connected to the transformer in a fixed-frequency manner; therefore, when the input voltage is low, the RMS current and peak current will be larger, and the current-resistant one will be lower. Power components cannot be used; a lot of electrical energy is turned into heat, and transformers tend to go into saturation and lose their inductive properties.

Therefore, the efficiency of the related art power supply device is not good when the input voltage is low.

Utility model content

In order to improve the above-mentioned shortcomings of the prior art, the purpose of the utility model is to provide a power supply device with variable switching frequency.

In order to achieve the above purpose, the utility model provides a power supply device with variable switching frequency, which includes:

a main transformer;

a voltage detection unit electrically connected to the main transformer;

a pulse width modulation control unit, the pulse width modulation control unit is electrically connected to the voltage detection unit; and

A switch unit, the switch unit is electrically connected to the pulse width modulation control unit and the main transformer.

The above-mentioned power supply device with variable switching frequency is applied to an AC power supply device and a load device, and it is characterized in that the power supply device with variable switching frequency further includes:

an input filter unit electrically connected to the main transformer; and

An input rectification unit, the input rectification unit is electrically connected to the input filter unit.

The above-mentioned variable switching frequency power supply device further includes:

an output rectification unit electrically connected to the main transformer; and

An output filtering unit, the output filtering unit is electrically connected to the output rectifying unit and the load device.

The above-mentioned variable switching frequency power supply device further includes:

a voltage feedback unit, the voltage feedback unit is electrically connected to the output filter unit, the load device and the pulse width modulation control unit;

a voltage stabilizing unit electrically connected to the main transformer and the pulse width modulation control unit; and

An electromagnetic interference filtering unit is electrically connected to the AC power supply device and the input rectifying unit.

In the above power supply device with variable switching frequency, the voltage detection unit is a voltage sampling circuit.

In the above power supply device with variable switching frequency, the pulse width modulation control unit is a pulse width modulation controller, the switch unit is a transistor switch, the input filter unit is a filter capacitor, and the input rectifier unit is A bridge rectifier, the output rectification unit is a diode, the output filter unit is a filter capacitor, the voltage feedback unit is a voltage feedback circuit, the voltage stabilization unit is a voltage stabilization circuit, and the electromagnetic interference filter unit is an electromagnetic Interference filter.

The effect of the utility model is to improve the efficiency of the power supply when the input voltage is low.

The utility model will be described in detail below in conjunction with the accompanying drawings and specific embodiments, but not as a limitation of the utility model.

Description of drawings

Fig. 1 is the block diagram of the first embodiment of the power supply device with variable switching frequency of the present invention;

FIG. 2 is a block diagram of the second embodiment of the variable switching frequency power supply device of the present invention.

Among them, reference signs

Power supply unit with variable switching frequency 10

AC power supply unit 20

Output Power 22

Load device 30

main transformer 102

Voltage detection unit 104

Pulse Width Modulation Control Unit 106

Switch unit 108

Input voltage 110

Output voltage 112

Input filter unit 114

Input rectification unit 116

Output rectification unit 118

Output filter unit 120

Voltage Feedback Unit 122

voltage stabilizing unit 124

EMI filter unit 126

Detailed ways

Below in conjunction with accompanying drawing, structural principle and working principle of the present utility model are specifically described:

Please refer to FIG. 1 , which is a block diagram of a first embodiment of a power supply device with variable switching frequency according to the present invention. A variable switching frequency power supply device 10 includes a main transformer 102 , a voltage detection unit 104 , a PWM control unit 106 and a switch unit 108 .

The voltage detection unit 104 is electrically connected to the main transformer 102; the pulse width modulation control unit 106 is electrically connected to the voltage detection unit 104; the switch unit 108 is electrically connected to the pulse width modulation control unit 106 and the pulse width modulation control unit 106 main transformer 102 .

According to a switching frequency of the switching unit 108, the main transformer 102 converts an input voltage 110 into an output voltage 112; the voltage detection unit 104 detects the input voltage 110 and notifies the pulse width modulation control unit 106; according to the input voltage 110 , the PWM control unit 106 controls the switching frequency of the switch unit 108 .

In a first specific embodiment, when the absolute voltage value of the input voltage 110 is greater than a third critical voltage value, the pulse width modulation control unit 106 controls the switching frequency of the switching unit 108 so that the switching unit 108 The switching frequency of becomes a third frequency.

When the absolute voltage value of the input voltage 110 is not greater than the third critical voltage value, the PWM control unit 106 controls the switching frequency of the switching unit 108 so that the switching frequency of the switching unit 108 becomes a first Four frequencies.

Wherein, the third frequency and the fourth frequency are different; the third frequency is smaller than the fourth frequency. The third threshold voltage value may be, for example but not limited to, 150V; the third frequency may be, for example but not limited to, 65KHz; the fourth frequency may be, for example but not limited to, 100KHz.

Moreover, in a second specific embodiment, when the absolute voltage value of the input voltage 110 increases and is greater than a first critical voltage value, the pulse width modulation control unit 106 controls the switching frequency of the switch unit 108, The switching frequency of the switch unit 108 is made to be a first frequency.

When the absolute voltage value of the input voltage 110 increases and is not greater than the first critical voltage value, the pulse width modulation control unit 106 controls the switching frequency of the switching unit 108 so that the switching frequency of the switching unit 108 does not Change.

When the absolute voltage value of the input voltage 110 decreases and is less than a second critical voltage value, the PWM control unit 106 controls the switching frequency of the switching unit 108 so that the switching frequency of the switching unit 108 becomes a second frequency.

When the absolute voltage value of the input voltage 110 decreases and is not less than the second critical voltage value, the pulse width modulation control unit 106 controls the switching frequency of the switching unit 108 so that the switching frequency of the switching unit 108 does not Change.

Wherein, the first critical voltage value and the second critical voltage value are different; the first critical voltage value is greater than the second critical voltage value. The first frequency and the second frequency are different; the first frequency is smaller than the second frequency. The first critical voltage value may be, for example but not limited to, 160 volts, the second critical voltage value may be, for example but not limited to, 140 volts, the first frequency may be, for example but not limited to, 65KHz, and the second frequency may be For example but not limited to 100KHz.

The process of the above-mentioned second embodiment is similar to the hysteresis effect; thereby, the PWM control unit 106 can avoid frequently changing the switching frequency of the switching unit 108, thus protecting the variable switching frequency. Components of the power supply device 10 .

Please refer to FIG. 2 , which is a block diagram of a second embodiment of the variable switching frequency power supply device of the present invention. The description of the components shown in FIG. 2 is similar to that in FIG. 1 , and will not be repeated here for the sake of brevity. Furthermore, the variable switching frequency power supply device 10 is applied to an AC power supply device 20 and a load device 30; the variable switching frequency power supply device 10 further includes an input filter unit 114, an input rectification unit 116 . An output rectifying unit 118 , an output filtering unit 120 , a voltage feedback unit 122 , a voltage stabilizing unit 124 and an electromagnetic interference filtering unit 126 .

The input filter unit 114 is electrically connected to the main transformer 102; the input rectifier unit 116 is electrically connected to the input filter unit 114; the output rectifier unit 18 is electrically connected to the main transformer 102; the output filter unit 120 is electrically connected connected to the output rectifying unit 118 and the load device 30; the voltage feedback unit 122 is electrically connected to the output filter unit 120, the load device 30 and the pulse width modulation control unit 106; the voltage stabilizing unit 124 is electrically connected To the main transformer 102 and the PWM control unit 106 ; the EMI filtering unit 126 is electrically connected to the AC power supply device 20 and the input rectifying unit 116 .

The voltage detection unit 104 can be, for example but not limited to, a voltage sampling circuit; an output power 22 of the AC power supply device 20 can be, for example but not limited to, between 90 volts and 265 volts; the pulse width modulation control The unit 106 can be, for example but not limited to, a pulse width modulation controller; the switch unit 108 can be, for example but not limited to, a transistor switch; the input filter unit 114 can be, for example but not limited to, a filter capacitor; the input The rectifying unit 116 may be, for example but not limited to, a bridge rectifier; the output rectifying unit 118 may be, for example but not limited to, a diode; the output filter unit 120 may be, for example but not limited to, a filter capacitor; the voltage feedback unit 122 may be, for example but not limited to, a voltage feedback circuit; the voltage stabilizing unit 124 may be, for example but not limited to, a voltage stabilizing circuit; the electromagnetic interference filtering unit 126 may be, for example but not limited to, an electromagnetic interference filter.

The voltage detection unit 104 shown in FIG. 2 is electrically connected to the main transformer 102 and the input filter unit 114, so the voltage detection unit 104 detects the input voltage 110 to obtain the absolute voltage value of the input voltage 110; however , the voltage detection unit 104 can also be electrically connected to the AC power supply device 20, so the voltage detection unit 104 detects the output power 22 of the AC power supply device 20 to obtain the input voltage 110 (the output power 22) The absolute value of this voltage.

Furthermore, the voltage detecting unit 104 can also be electrically connected to the input rectifying unit 116 and the electromagnetic interference filtering unit 126 , or can be electrically connected to the input rectifying unit 116 and the input filtering unit 114 .

The utility model comprises the following characteristics (advantages):

1. When the absolute value of the voltage of the input voltage 110 (the output power 22 ) is relatively large, the switching frequency of the switch unit 108 is low; when the absolute value of the voltage of the input voltage 110 (the output power 22 ) is relatively high Hours, the switching frequency of the switch unit 108 is relatively high.

2. When the switching frequency of the switching unit 108 is high, the RMS current and peak current can be reduced, power elements with lower current resistance can be used, and the magnetic flux can be reduced, so the magnetizing inductance can be increased to improve efficiency, or Under the same magnetizing inductance, the number of turns of the main transformer 102 can be reduced to use a smaller iron core to reduce volume.

3. Improve the efficiency of the power supply when the input voltage is low.

4. The utility model is suitable for continuous conduction mode (continuous conduction mode).

Of course, the utility model can also have other various embodiments, and those skilled in the art can make various corresponding changes and deformations according to the utility model without departing from the spirit and essence of the utility model, but These corresponding changes and deformations should all belong to the protection scope of the appended claims of the present utility model.

Claims (6)

1. a power supply device for changeable switch frequency, is characterized in that, comprises:

One main transformer;

One voltage detection unit, this voltage detection unit is electrically connected to this main transformer;

One pulse width modulation control unit, this pulse width modulation control unit is electrically connected to this voltage detection unit; And

One switch element, this switch element is electrically connected to this pulse width modulation control unit and this main transformer.

2. the power supply device of changeable switch frequency according to claim 1, is applied to an AC power feeding mechanism and a load device, it is characterized in that, the power supply device of this changeable switch frequency more comprises:

One input filter unit, this input filter unit is electrically connected to this main transformer; And

One input rectifying unit, this input rectifying unit is electrically connected to this input filter unit.

3. the power supply device of changeable switch frequency according to claim 2, is characterized in that, more comprises:

One output rectification unit, this output rectification unit is electrically connected to this main transformer; And

One output filtering unit, this output filtering unit is electrically connected to this output rectification unit and this load device.

4. the power supply device of changeable switch frequency according to claim 3, is characterized in that, more comprises:

One voltage feedback unit, this voltage feedback unit is electrically connected to this output filtering unit, this load device and this pulse width modulation control unit;

One voltage regulation unit, this voltage regulation unit is electrically connected to this main transformer and this pulse width modulation control unit; And

One EMI Filtering unit, this EMI Filtering unit is electrically connected to this AC power feeding mechanism and this input rectifying unit.

5. the power supply device of changeable switch frequency according to claim 1, is characterized in that, this voltage detection unit is a voltage sample circuit.

6. the power supply device of changeable switch frequency according to claim 5, it is characterized in that, this pulse width modulation control unit is a pulse width modulation controller, this switch element is a transistor switch, this input filter unit is a filter capacitor, this input rectifying unit is a bridge rectifier, this output rectification unit is a diode, this output filtering unit is a filter capacitor, this voltage feedback unit is a voltage feedback circuit, this voltage regulation unit is a voltage stabilizing circuit, and this EMI Filtering unit is an Electromagnetic interference filter.