CN207124553U - Switching Power Supply and laser projection with under-voltage point protection - Google Patents

Abstract

The utility model provides a switching power supply with undervoltage point protection, which includes a voltage input circuit unit, an LLC half-bridge resonant controller and a voltage feedback unit; the LLC half-bridge resonant controller includes an input voltage signal detection input terminal, a voltage Output end and voltage feedback input end, the voltage input circuit unit is electrically connected to the input voltage signal detection input end, one end of the voltage feedback unit is connected to the voltage output end, and the other end is connected to the voltage feedback The input terminal forms a feedback circuit; the voltage input circuit unit includes a voltage input terminal and a voltage divider circuit for reducing the undervoltage point, and the voltage divider circuit is connected in series with the voltage input terminal and the input voltage signal detection input between the ends. The utility model also provides a laser projector. The switching power supply and laser projector with undervoltage point protection of the utility model can be normally started in a 0-degree environment, and the undervoltage point is low and the starting stability is good.

Description

Switching power supply and laser projector with undervoltage point protection

technical field

The utility model belongs to the technical field of power supplies, in particular to a switching power supply with undervoltage point protection and a laser projector.

Background technique

With the advent of the intelligent age, electronic equipment has become a part of life, and various electronic equipment emerges in an endless stream. The power supply has become a necessary component for the stable operation of electronic equipment, such as laser projectors. Take the laser projector as an example:

At present, the power supply of laser projectors in the related art uses an LLC half-bridge resonant controller to control DC-DC conversion. The power supply includes an LLC resonant half-bridge controller, a voltage feedback unit, and an input circuit unit. The LLC resonant half-bridge The controller includes an input voltage signal detection input terminal, a voltage output terminal and a voltage feedback input terminal, the input circuit unit is connected to the input voltage signal detection input terminal, one end of the voltage feedback unit is connected to the voltage output terminal, The other end is connected to the voltage feedback input end to form a feedback circuit.

However, in actual use, when the ambient temperature is 0 degrees and the input voltage (that is, PFC) is 90V, the actual voltage value of the voltage signal detection input terminal is less than its threshold turn-on voltage of 1.3V, and the LLC cannot start working normally. , the power fails to turn on and cannot work normally. Therefore, the stability of the power supply and the laser projector or other electronic equipment using the power supply is poor.

Therefore, it is necessary to provide a new switching power supply and projector with undervoltage point protection to solve the above problems.

Utility model content

Aiming at the above deficiencies in the prior art, the utility model proposes a switching power supply and projector with low undervoltage point and good start-up stability with undervoltage point protection.

The utility model provides a switching power supply with undervoltage point protection, which includes a voltage input circuit unit, an LLC half-bridge resonant controller and a voltage feedback unit; the LLC half-bridge resonant controller includes an input voltage signal detection input terminal, a voltage output end and a voltage feedback input end, the voltage input circuit unit is electrically connected to the input voltage signal detection input end, one end of the voltage feedback unit is electrically connected to the voltage output end, and the other end is electrically connected to the voltage Feedback input terminal and form a feedback circuit; the voltage input circuit unit includes a voltage input terminal and a voltage divider circuit for reducing the undervoltage point of the circuit to below 73V, and the voltage divider circuit is connected in series with the voltage input terminal and the between the input voltage signal detection input terminals.

Preferably, the voltage dividing circuit includes a first voltage dividing unit and a second voltage dividing unit, the first voltage dividing unit is connected in series between the voltage input terminal and the input voltage signal detection input terminal, and the second voltage dividing unit One end of the two voltage division units is electrically connected between the voltage division resistance unit and the input voltage signal detection input end, and the other end is grounded.

Preferably, the first voltage dividing unit includes a first resistor, a second resistor and a third resistor connected in series with each other, and the second voltage dividing unit is a voltage dividing component with adjustable resistance.

Preferably, the resistance values of the first resistor, the second resistor and the third resistor are all 2MR, and the resistance value range of the voltage dividing component is adjustable between 110KR~122.4KR.

Preferably, the voltage dividing component is a sliding rheostat.

Preferably, the resistance value of the voltage dividing component is 110KR.

Preferably, the second voltage dividing unit is a fixed value resistor, and the resistance value of the fixed value resistor can be any value between 110KR~122.4KR.

Preferably, the total resistance of the first voltage dividing unit is 6MR.

Preferably, the voltage feedback unit is an optocoupler feedback circuit.

The utility model also provides a laser projector, including the switching power supply provided by the utility model with undervoltage point protection.

Compared with the related technology, the switching power supply with undervoltage point protection of the utility model adds a voltage divider circuit for reducing the undervoltage point of the circuit to the design of the voltage input circuit unit, through which the voltage divider circuit realizes all The undervoltage point of the switching power supply is reduced to below 73V, so that the switching power supply and the laser projector can be started normally at 0 degrees, with good stability and reliability.

Description of drawings

Below in conjunction with accompanying drawing, describe the utility model in detail. Through the detailed description in conjunction with the following drawings, the content of the above or other aspects of the present invention will become clearer and easier to understand. In the attached picture:

FIG. 1 is a structural schematic diagram of a switching power supply with undervoltage point protection of the present invention.

Detailed ways

The specific embodiment of the utility model will be described in detail below in conjunction with the accompanying drawings.

The specific implementations/embodiments described here are specific specific implementations of the present utility model, and are used to illustrate the concept of the present utility model. Limitations on the scope of utility models. In addition to the embodiments described here, those skilled in the art can also adopt other obvious technical solutions based on the claims of the application and the contents disclosed in the description, and these technical solutions include adopting any obvious changes made to the embodiments described here. The replacement and modified technical solutions are all within the protection scope of the present utility model.

Please refer to FIG. 1 , the utility model provides a switching power supply 10 with undervoltage point protection, including a voltage input circuit unit 1 , an LLC half-bridge resonant controller 2 and a voltage feedback unit 3 .

The LLC half-bridge resonant controller 2 includes an input voltage signal detection input terminal VSEN, a voltage output terminal 21 and a voltage feedback input terminal FB.

The voltage input circuit unit 1 is electrically connected to the input voltage signal detection input terminal VSEN.

In this embodiment, the voltage input circuit unit 1 includes a voltage input terminal PFC and a voltage dividing circuit 11 for reducing the undervoltage point of the circuit. The voltage divider circuit 11 is connected in series between the voltage input terminal PFC and the input voltage signal detection input terminal VSEN.

Specifically, the voltage dividing circuit 11 includes a first voltage dividing unit 111 and a second voltage dividing unit 112 .

The first voltage dividing unit 111 is connected in series between the voltage input terminal PFC and the input voltage signal detection input terminal VSEN for forming voltage division protection for the circuit.

The first voltage dividing unit 111 may include only one resistor, or may include more than two resistors connected in series, and the resistance values of each resistor may not necessarily be equal, or include multiple resistors connected in parallel, or include multiple resistors connected in parallel. A resistor can be formed in parallel or in series. These are all feasible, and the principle is the same, as long as the resistance value within a certain range can be achieved.

In other words, as long as the resistance of RH104 / (RH104+RH61+RH62+RH72) is within a certain range, the range of this resistance makes the undervoltage point between 65V~73V.

In this embodiment, the first voltage dividing unit 111 includes a first resistor RH72 , a second resistor RH62 and a third resistor RH61 which are connected in series with each other and have equal resistance values.

Specifically, the resistance values of the first resistor RH72 , the second resistor RH62 and the third resistor RH61 of the first voltage dividing unit 111 are all 2MR, that is, 2MΩ. Of course, the structure of the first voltage dividing unit 111 is not limited thereto, as long as the total resistance value of the first voltage dividing unit 111 is 6MR, the number of resistors and the relationship of series or parallel connection are not limited.

One end of the second voltage dividing unit 112 is electrically connected between the first voltage dividing unit 111 and the input voltage signal detection input terminal VSEN, and the other end is grounded, and is mainly used for voltage dividing to make the undervoltage of the power supply 10 point lower. In this embodiment, the second voltage dividing unit 112 is a voltage divider with adjustable resistance, such as a resistor or other electronic devices with a certain resistance, which is feasible.

The resistance value of the second voltage dividing unit 112 ranges from 110KR to 122.4KR. Specifically, the second voltage dividing unit 112 is a voltage dividing component whose resistance value ranges from 110KR to 122.4KR, such as a sliding rheostat RH1.

Alternatively, the second voltage dividing unit 112 is a fixed-value resistor RH104, and the resistance value of the fixed-value resistor RH104 can be any value between 110KR˜122.4KR.

In this embodiment, the second voltage dividing unit 112 is specifically selected as a sliding rheostat RH1 with a resistance range of 110KR˜122.4KR.

The voltage feedback unit 3 is specifically an optocoupler feedback circuit. One terminal of the voltage feedback unit 3 is electrically connected to the voltage output terminal 21 , and the other terminal of the voltage feedback unit 3 is electrically connected to the voltage feedback input terminal FB to form a feedback circuit to realize overvoltage protection.

Taking the components of this embodiment as an example, the resistance values of the second resistor RH62 and the third resistor RH61 are both 2MR, the second voltage dividing unit 112 is selected as a resistor RH104 with a resistance value of 110KR, and the voltage input terminal When the PFC input voltage is 90V:

Then substitute into the formula to get:

VSEN = [ RH104 / (RH104+RH61+RH62+RH72) ] * PFC

It can be deduced that the voltage input terminal PFC=72.2V, then this voltage is the undervoltage point of the power input.

After verification, when the ambient temperature of the switching power supply 10 with undervoltage point protection is 0 degrees, and the input voltage of the voltage input terminal PFC is 90V, the switching power supply 10 with undervoltage point protection can work normally, and at normal temperature , when the PFC input voltage is 90V, the whole machine does not fail to turn on.

In addition, the resistor RH104 of the second voltage dividing unit 112 is replaced by a sliding rheostat RH1 with adjustable resistance, so as to adjust the voltage dividing ratio from the input voltage of the voltage input terminal PFC to the A node, and then realize the control of the The undervoltage point of the switching power supply 10 for undervoltage point protection.

For example, if the second voltage dividing unit 112 is replaced by a sliding rheostat RH1, and its resistance value is adjusted to 110KR or greater, then the voltage at the voltage input terminal PFC will be divided to the value of node A to reach its threshold value and turn on The voltage is 1.3V, the switching power supply 10 with undervoltage point protection or the electronic equipment using it such as a projector is placed indoors and the temperature is set to 0 degrees. The projector plays video normally and works normally for 24 hours without shutting down. state.

When the resistance value of the sliding rheostat RH1 is changed to 110KR~122.4KR, and the value of the input voltage signal detection input terminal VSEN is its lower threshold value (1.3V), according to the principle of voltage division:

VSEN = [RH1 / (RH1+RH61+RH62+RH72)] * PFC

Therefore, it can be deduced that the value of PFC at the voltage input terminal is 65V~73V, and 65V~73V is the undervoltage protection point range of the switching power supply 10 with undervoltage point protection.

It should be noted that when the resistance value of the second voltage dividing unit 112 exceeds 122.4KR, the undervoltage point of the switching power supply 10 with undervoltage point protection will be lower than 65V, which may cause some devices to start No, therefore, the resistance range of the second voltage dividing unit 112 is preferably 110KR˜122.4KR.

The utility model also provides a laser projector (not shown), which includes the above-mentioned switching power supply 10 with undervoltage point protection.

Compared with the related technology, the switching power supply with undervoltage point protection of the utility model adds a voltage divider circuit for reducing the undervoltage point of the circuit to the design of the voltage input circuit unit, through which the voltage divider circuit realizes all The undervoltage point of the switching power supply is reduced to below 73V, so that the switching power supply and the laser projector can be started normally at 0 degrees, and the stability and reliability are good after starting.

It should be noted that the various embodiments described above with reference to the accompanying drawings are only used to illustrate the utility model rather than limit the scope of the utility model, those of ordinary skill in the art should understand that without departing from the spirit and scope of the utility model Any modifications or equivalent replacements made to the present utility model under the premise of the present utility model shall be covered within the scope of the present utility model. Further, words appearing in the singular include the plural and vice versa unless the context otherwise requires. Additionally, all or a portion of any embodiment may be utilized with all or a portion of any other embodiment, unless stated otherwise.

Claims (10)

1. A switching power supply with undervoltage point protection, comprising a voltage input circuit unit, an LLC half-bridge resonant controller and a voltage feedback unit; said LLC half-bridge resonant controller includes an input voltage signal detection input, a voltage output and Voltage feedback input terminal, the voltage input circuit unit is electrically connected to the input voltage signal detection input terminal, one end of the voltage feedback unit is electrically connected to the voltage output end, and the other end is electrically connected to the voltage feedback input terminal and form a feedback circuit, characterized in that the voltage input circuit unit includes a voltage input terminal and a voltage divider circuit for reducing the undervoltage point of the circuit to below 73V, and the voltage divider circuit is connected in series with the voltage input terminal and between the input voltage signal detection input. 2. The switching power supply with undervoltage point protection according to claim 1, wherein the voltage dividing circuit comprises a first voltage dividing unit and a second voltage dividing unit, and the first voltage dividing unit is connected in series with the Between the voltage input end and the input voltage signal detection input end, one end of the second voltage dividing unit is electrically connected between the voltage dividing resistance unit and the input voltage signal detection input end, and the other end is grounded. 3. The switching power supply with undervoltage point protection according to claim 2, wherein the first voltage dividing unit includes a first resistor, a second resistor and a third resistor connected in series with each other, the second resistor The voltage dividing unit is a voltage dividing component with adjustable resistance value. 4. The switching power supply with undervoltage point protection according to claim 3, wherein the resistance values of the first resistor, the second resistor and the third resistor are all 2MR, and the divided voltage The resistance value range of components is adjustable between 110KR~122.4KR. 5. The switching power supply with undervoltage point protection according to claim 3, wherein the voltage dividing component is a sliding rheostat. 6. The switching power supply with undervoltage point protection according to claim 4, wherein the resistance value of the voltage dividing component is 110KR. 7. The switching power supply with undervoltage point protection according to claim 2, wherein the second voltage dividing unit is a fixed-value resistor, and the resistance value of the fixed-value resistor can be between 110KR~122.4KR any value of . 8. The switching power supply with undervoltage point protection according to claim 7, wherein the total resistance of the first voltage dividing unit is 6MR. 9. The switching power supply with undervoltage point protection according to any one of claims 1 to 8, wherein the voltage feedback unit is an optocoupler feedback circuit. 10. A laser projector, characterized in that it comprises the switching power supply with undervoltage point protection according to any one of claims 1 to 9.