CN112134473B

CN112134473B - Power supply

Info

Publication number: CN112134473B
Application number: CN201910549595.9A
Authority: CN
Inventors: 詹子增
Original assignee: Acer Inc
Current assignee: Acer Inc
Priority date: 2019-06-24
Filing date: 2019-06-24
Publication date: 2022-03-22
Anticipated expiration: 2039-06-24
Also published as: CN112134473A

Abstract

A power supply, comprising: an input stage circuit, a controller, a multi-stage resonance circuit, a transformer, and an output stage circuit. The input stage circuit generates a switching potential according to an input potential. The controller generates a first control potential and a second control potential according to the switching potential. The multi-order resonant circuit provides a reference potential at a first node. The multi-level resonant circuit includes a first current path and a second current path, wherein the first node is coupled to a ground potential via the first current path and the second current path, respectively. The first current path and the second current path are selectively switched on or off in accordance with a first control potential and a second control potential. The output stage circuit generates an output potential according to a transformation potential of the transformer.

Description

Power supply

Technical Field

The present invention relates to a power supply, and more particularly to a power supply capable of increasing output stability.

Background

When the electronic device is powered by an external power source, the external power source is not stable enough, which sometimes causes undesirable phenomena such as "Voltage Dips" (or "Short interruptions"). Fig. 1 is a graph showing the relationship between the input potential of the external power source and time. As shown in fig. 1, during the first period T1, the input potential of the external power source is reduced by about 30%, which can be regarded as the aforementioned voltage sag phenomenon; in addition, in the second period T2, the input potential of the external power supply is lowered by about 100%, which may be regarded as the aforementioned short-time interruption phenomenon.

Conventional power supplies typically provide only a very short hold-up Time (Holding-up Time) in the face of a momentary drop or short interruption in the voltage of the external power supply, which is difficult to comply with International Electrotechnical Commission (IEC) specifications. In view of the above, a new solution is needed to overcome the problems in the prior art.

Disclosure of Invention

In a preferred embodiment, the present invention provides a power supply, comprising: an input stage circuit for generating a switching potential according to an input potential; a controller for detecting the switching potential, wherein the controller generates a first control potential and a second control potential according to the switching potential; a multi-level resonant circuit providing a reference potential at a first node, wherein the multi-level resonant circuit comprises a first current path and a second current path, the first node is coupled to a ground potential via the first current path and the second current path, respectively, the first current path is selectively turned on or off according to the first control potential, and the second current path is selectively turned on or off according to the second control potential; a transformer for generating a transformation potential according to a potential difference between the switching potential and the reference potential; and an output stage circuit for generating an output potential according to the transformed potential.

Drawings

Fig. 1 is a graph showing the relationship between the input potential of the external power source and time.

Fig. 2 is a schematic diagram illustrating a power supply according to an embodiment of the invention.

Fig. 3 is a schematic diagram illustrating a power supply according to an embodiment of the invention.

Fig. 4 is an equivalent circuit diagram of a second-order resonant tank according to an embodiment of the invention.

FIG. 5 is a diagram showing a potential waveform of the power supply according to an embodiment of the invention.

Fig. 6 is a schematic diagram illustrating a power supply according to another embodiment of the invention.

Fig. 7 is an equivalent circuit diagram showing a third-order resonant tank according to another embodiment of the invention.

Fig. 8 is a diagram showing a potential waveform of a power supply according to another embodiment of the invention.

Description of reference numerals:

200. 300, 600-power supply;

210. 310-an input stage circuit;

220. 320, 620-controller;

230. 330, 630-multiple order resonance circuit;

231. 331-a first current path;

232. 332 to a second current path;

240. 340-transformer;

250. 350-output stage circuit;

312-ac-to-dc converter;

333 to a third current path;

341 to a main coil;

342 to secondary coil;

c1-first capacitor;

c2-second capacitor;

c3-third capacitor;

d1-diode;

l1-first inductor;

l2-a second inductor;

m1-first transistor;

m2-second transistor;

m3 third transistor;

n1-first node;

n2-second node;

n3-third node;

n4-fourth node;

n5-fifth node;

NIN-input node;

NOUT-output node;

t1-first period;

t2-second period;

VC 1-a first control potential;

VC 2-a second control potential;

VC3 to a third control potential;

VD-potential difference;

VIN-input potential;

VOUT-output potential;

VR to reference potential;

VSS to ground potential;

VT-transformation potential;

VTH 1-first critical potential;

VTH 2-second critical potential;

VTH 3-third critical potential;

VW-switching potential.

Detailed Description

In order to make the objects, features and advantages of the present invention comprehensible, specific embodiments accompanied with figures are described in detail below.

Fig. 2 is a schematic diagram illustrating a power supply 200 according to an embodiment of the invention. For example, the power supply 200 may be applied to a desktop computer, a notebook computer, or an integrated computer. As shown in fig. 2, the power supply 200 includes: an input stage circuit 210, a controller 220, a multi-stage resonant circuit 230, a transformer 240, and an output stage circuit 250. The input stage circuit 210 generates a switching potential VW according to an input potential VIN. The input potential VIN may be derived from an external power source, wherein the input potential VIN may be an ac potential with any frequency and any amplitude. For example, the frequency of the input voltage VIN may be about 50Hz, and the square root mean of the amplitude of the input voltage VIN may be about 100V, but is not limited thereto. The controller 220 can be an integrated circuit chip that first detects the switching potential VW and then generates a first control potential VC1 and a second control potential VC2 according to the switching potential VW. The multi-stage resonant circuit 230 provides a reference potential VR at a first node N1. In detail, the multi-level resonant circuit 230 includes a first current path 231 and a second current path 232, wherein the first node N1 is coupled to a ground potential VSS (e.g., 0V) via the first current path 231 and the second current path 232, respectively. The first current path 231 is selectively turned on (Closed) or turned off (Open) according to the first control potential VC1, and the second current path 232 is selectively turned on or turned off according to the second control potential VC 2. The transformer 240 generates a transformation potential VT according to a potential difference VD between the switching potential VW and the reference potential VR. The output stage circuit 250 generates an output voltage VOUT according to the transformed voltage VT. The output potential VOUT may be a dc potential having an arbitrary level. For example, the level of the output potential VOUT may be substantially constant 19V, but is not limited thereto. This circuit design helps to increase the output stability of the power supply 200 according to actual measurement results. It should be noted that, although not shown in fig. 2, the power supply 200 may also include other components, such as: a Voltage Regulator or and a negative feedback circuit.

The following embodiment will describe the detailed structure and operation of the power supply 200. It must be understood that these drawings and descriptions are only exemplary and are not intended to limit the scope of the present invention.

Fig. 3 is a schematic diagram illustrating a power supply 300 according to an embodiment of the invention. In the embodiment of fig. 3, the power supply 300 has an input node NIN and an output node NOUT, and includes an input stage circuit 310, a controller 320, a multi-stage resonant circuit 330, a transformer 340, and an output stage circuit 350. The input node NIN of the power supply 300 can receive an input voltage VIN from an external power source, and the output node NOUT of the power supply 300 can be used for outputting an output voltage VOUT to an electronic device (e.g., a computer). The multi-order resonant circuit 330 includes a first current path 331 and a second current path 332. The multi-level resonant circuit 230 provides a reference potential VR at a first node N1, wherein the first node N1 is coupled to a ground potential VSS via the first current path 331 and the second current path 332, respectively.

The input stage circuit 310 includes an ac-to-dc converter 312 and a first capacitor C1. The ac-dc converter 312 can convert the input potential VIN at the input node NIN to a switching potential VW at a second node N2. The first capacitor C1 has a first terminal and a second terminal, wherein the first terminal of the first capacitor C1 is coupled to the second node N2, and the second terminal of the first capacitor C1 is coupled to the ground potential VSS. The controller 320 is used for detecting the switching potential VW and generating a first control potential VC1 and a second control potential VC2 according to the switching potential VW. In some embodiments, the first control potential VC1 is a Clock (Clock) with arbitrary frequency and arbitrary duty cycle.

The first current path 331 of the multi-step resonant circuit 330 includes a first transistor M1. For example, the first transistor M1 may be an nmos field effect transistor. The first transistor M1 has a control terminal, a first terminal, and a second terminal, wherein the control terminal of the first transistor M1 is for receiving the first control potential VC1, the first terminal of the first transistor M1 is coupled to the ground potential VSS, and the second terminal of the first transistor M1 is coupled to the first node N1.

The second current path 332 of the multi-step resonant circuit 330 includes a second capacitor C2 and a second transistor M2. For example, the second transistor M2 may be an nmos field effect transistor. The second capacitor C2 has a first terminal and a second terminal, wherein the first terminal of the second capacitor C2 is coupled to the first node N1, and the second terminal of the second capacitor C2 is coupled to a third node N3. The second transistor M2 has a control terminal, a first terminal, and a second terminal, wherein the control terminal of the second transistor M2 is used for receiving the second control potential VC2, the first terminal of the second transistor M2 is coupled to the ground potential VSS, and the second terminal of the second transistor M2 is coupled to the third node N3.

The transformer 340 includes a primary winding 341, a secondary winding 342, and a first inductor L1. The primary winding 341 has a first terminal and a second terminal, wherein the first terminal of the primary winding 341 is coupled to the second node N2 for receiving the switching potential VW, and the second terminal of the primary winding 341 is coupled to the first node N1 for receiving the reference potential VR. The secondary winding 342 has a first end and a second end, wherein the first end of the secondary winding 342 is coupled to a fourth node N4 for outputting a transformed potential VT, and the second end of the secondary winding 342 is coupled to the ground potential VSS. The level of the transformation potential VT may be directly proportional to a potential difference VD between the switching potential VW and the reference potential VR. The first inductor L1 may represent an excitation inductance value of the transformer 340. The first inductor L1 has a first terminal and a second terminal, wherein the first terminal of the first inductor L1 is coupled to the second node N2, and the second terminal of the first inductor L1 is coupled to the first node N1.

The output stage circuit 350 includes a diode D1 and a third capacitor C3. The diode D1 has an anode and a cathode, wherein the anode of the diode D1 is coupled to the fourth node N4, and the cathode of the diode D1 is coupled to the output node NOUT for outputting the output voltage VOUT. The third capacitor C3 has a first terminal and a second terminal, wherein the first terminal of the third capacitor C3 is coupled to the output node NOUT, and the second terminal of the third capacitor C3 is coupled to the ground potential VSS.

The operation principle of the power supply 300 may be as follows. Initially, the switching potential VW is equal to the ground potential VSS, and the second transistor M2 is disabled. Then, the power supply 300 is coupled to an external power source to receive the input potential VIN, such that the first capacitor C1 is charged and the switching potential VW gradually increases. When detecting that the switching voltage VW has risen to reach a first threshold voltage VTH1, the controller 320 enables the second transistor M2 by pulling up the second control voltage VC 2. Accordingly, the first capacitor C1, the first inductor L1, and the second capacitor C2 start resonating with each other to form a two-step resonant tank. Fig. 4 is an equivalent circuit diagram of a second-order resonant tank according to an embodiment of the invention.

Fig. 5 is a diagram illustrating a potential waveform of the power supply 300 according to an embodiment of the invention. According to the measurement results of fig. 5, after the second-order resonant tank is used, the switching potential VW is raised to a second threshold potential VTH2, wherein the second threshold potential VTH2 may be substantially equal to 2 times the first threshold potential VTH 1. It should be noted that when the external power supply is dropped or interrupted for a short time, the holding time of the power supply 300 can be expressed by the following equation (1):

where "C1" represents the capacitance value of the first capacitor C1, "VW" represents the level of the switching potential VW, "P" represents the output power of the power supply 300, and "T" represents the sustain time of the power supply 300.

As can be seen from equation (1), the holding time of the power supply 300 is proportional to the square of the switching potential VW. Therefore, the design of adding the second-order resonant tank to pull up the switching potential VW can greatly increase the holding time of the power supply 300. Assuming that the frequency of the input voltage VIN is 50Hz and the square root of the amplitude of the input voltage VIN is 100V, the operation characteristics of the conventional power supply and the proposed power supply 300 can be compared as listed in the following table one:

table one: comparison of a conventional power supply with the proposed power supply 300

In some embodiments, the component parameters of the power supply 300 may be as follows. The capacitance of the first capacitor C1 may be between 90 μ F and 110 μ F, preferably 100 μ F. The second capacitor C2 may have a capacitance value between 297pF and 363pF, preferably 330 pF. The capacitance of the third capacitor C3 may be between 612 μ F and 748 μ F, preferably 680 μ F. The Inductance value (Inductance) of the first inductor L1 may be between 450mH and 550mH, preferably 500 mH. The ratio of the number of turns of the primary coil 341 to the secondary coil 342 may be between 1 and 10, preferably 5. The above parameter ranges are derived from a plurality of experimental results, which help to optimize the conversion efficiency and the maintenance time of the power supply 300.

Fig. 6 is a schematic diagram illustrating a power supply 600 according to another embodiment of the invention. Fig. 6 is similar to fig. 3. In the embodiment of fig. 6, a controller 620 of the power supply 600 further generates a third control potential VC3 according to the switching potential VW, and a multi-stage resonant circuit 630 of the power supply 600 further includes a third current path 333. In detail, the first node N1 of the multi-stage resonant circuit 630 is further coupled to the ground potential VSS via a third current path 333, wherein the third current path 333 is selectively turned on or off according to a third control potential VC 3.

The third current path 333 of the multi-step resonant circuit 630 includes a second inductor L2 and a third transistor M3. For example, the third transistor M3 may be an nmos field effect transistor. The second inductor L2 has a first terminal and a second terminal, wherein the first terminal of the second inductor L2 is coupled to the first node N1, and the second terminal of the second inductor L2 is coupled to a fifth node N5. For example, the inductance of the second inductor L2 may be between 4.5 μ H and 5.5 μ H, preferably 5 μ H. The third transistor M3 has a control terminal, a first terminal, and a second terminal, wherein the control terminal of the third transistor M3 is for receiving the third control potential VC3, the first terminal of the third transistor M3 is coupled to the ground potential VSS, and the second terminal of the third transistor M3 is coupled to the fifth node N5.

Similarly, the operating principle of the power supply 600 may be as follows. Initially, the third transistor M3 is disabled. When detecting that the switching voltage VW has risen to the second threshold voltage VTH2, which is higher than the first threshold voltage VTH1, the controller 620 enables the third transistor M3 by pulling up the third control voltage VC 3. Accordingly, the first capacitor C1, the first inductor L1, the second capacitor C2, and the second inductor L2 start to resonate with each other to form a Third-Order Resonant Loop. Fig. 7 is an equivalent circuit diagram showing a third-order resonant tank according to another embodiment of the invention.

Fig. 8 is a diagram showing potential waveforms of the power supply 600 according to another embodiment of the invention. According to the measurement results shown in FIG. 8, after the third-order resonant tank is used, the switching potential VW is raised to a third threshold potential VTH3, wherein the third threshold potential VTH3 may be substantially equal to the second threshold potential VTH2

And (4) doubling. As can be seen from equation (1), the holding time of the power supply 600 is proportional to the square of the switching potential VW. Therefore, the design of adding the third-order resonant tank to pull up the switching potential VW can further increase the holding time of the power supply 600. Assuming that the frequency of the input voltage VIN is 50Hz and the square root of the amplitude of the input voltage VIN is 100V, the operation characteristics of the conventional power supply and the proposed power supply 600 can be compared as shown in the following table two:

	maximum value of input potential	Maintenance time
			Conventional power supply	141V	15.4ms
Power supply
	600	400V	123ms

Table two: comparison of a conventional power supply with the proposed power supply 600

The present invention provides a novel power supply, which includes a multi-stage resonant circuit capable of increasing the stored energy of the capacitor. According to the actual measurement results, the power supply using the multi-stage resonant circuit can have a longer holding time to meet the international electrotechnical commission specifications. In addition, the design of pulling up the potential by times can also avoid the circuit elements from overload damage. Generally, the present invention has at least the advantage of higher output stability compared to the conventional design, so it is very suitable for various electronic devices.

It should be noted that the above-mentioned potential, current, resistance, inductance, capacitance, and other device parameters are not limitations of the present invention. The designer can adjust these settings according to different needs. The power supply of the present invention is not limited to the states illustrated in fig. 1 to 8. The present invention may include only any one or more features of any one or more of the embodiments of fig. 1-8. In other words, not all illustrated features may be implemented in a power supply of the present invention. Although the embodiments of the present invention use mosfet as an example, the present invention is not limited thereto, and other kinds of transistors can be used by those skilled in the art, such as: bipolar junction transistors, junction field effect transistors, fin field effect transistors, etc., without affecting the effect of the present invention.

Ordinal numbers such as "first," "second," "third," etc., in the specification and in the claims, do not have a sequential relationship with each other, but are used merely to identify two different elements having the same name.

Although the present invention has been described with reference to the preferred embodiments, it should be understood that various changes and modifications can be made therein by those skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

1. A power supply, comprising:

an input stage circuit for generating a switching potential according to an input potential;

a controller for detecting the switching potential, wherein the controller generates a first control potential and a second control potential according to the switching potential;

a multi-level resonant circuit providing a reference potential at a first node, wherein the multi-level resonant circuit comprises a first current path and a second current path, the first node is coupled to a ground potential via the first current path and the second current path, respectively, the first current path is selectively turned on or off according to the first control potential, and the second current path is selectively turned on or off according to the second control potential;

a transformer for generating a transformation potential according to a potential difference between the switching potential and the reference potential; and

an output stage circuit for generating an output potential according to the transformed potential,

the controller further generates a third control potential according to the switching potential, the first node is further coupled to the ground potential through the third current path, and the third current path is selectively turned on or off according to the third control potential.

2. The power supply of claim 1, wherein the input stage circuit comprises:

an AC-to-DC converter converting the input potential at an input node to the switching potential at a second node; and

a first capacitor having a first terminal and a second terminal, wherein the first terminal of the first capacitor is coupled to the second node and the second terminal of the first capacitor is coupled to the ground potential.

3. The power supply of claim 1, wherein the first current path of the multi-order resonant circuit comprises:

a first transistor having a control terminal, a first terminal, and a second terminal, wherein the control terminal of the first transistor is configured to receive the first control potential, the first terminal of the first transistor is coupled to the ground potential, and the second terminal of the first transistor is coupled to the first node.

4. The power supply of claim 1, wherein the second current path of the multi-order resonant circuit comprises:

a second capacitor having a first terminal and a second terminal, wherein the first terminal of the second capacitor is coupled to the first node and the second terminal of the second capacitor is coupled to a third node; and

a second transistor having a control terminal, a first terminal, and a second terminal, wherein the control terminal of the second transistor is configured to receive the second control potential, the first terminal of the second transistor is coupled to the ground potential, and the second terminal of the second transistor is coupled to the third node.

5. The power supply of claim 4, wherein the controller enables the second transistor when the switching voltage rises to a first threshold voltage.

6. The power supply of claim 2, wherein the transformer comprises:

a primary coil having a first end and a second end, wherein the first end of the primary coil is coupled to the second node for receiving the switching potential, and the second end of the primary coil is coupled to the first node for receiving the reference potential;

a secondary winding having a first end and a second end, wherein the first end of the secondary winding is coupled to a fourth node for outputting the transformed potential, and the second end of the secondary winding is coupled to the ground potential; and

a first inductor having a first end and a second end, wherein the first end of the first inductor is coupled to the second node and the second end of the first inductor is coupled to the first node.

7. The power supply of claim 6, wherein the output stage circuit comprises:

a diode having an anode and a cathode, wherein the anode of the diode is coupled to the fourth node and the cathode of the diode is coupled to an output node to output the output potential; and

a third capacitor having a first terminal and a second terminal, wherein the first terminal of the third capacitor is coupled to the output node and the second terminal of the third capacitor is coupled to the ground potential.

8. The power supply of claim 1, wherein the third current path of the multi-order resonant circuit comprises:

a second inductor having a first end and a second end, wherein the first end of the second inductor is coupled to the first node and the second end of the second inductor is coupled to a fifth node; and

a third transistor having a control terminal, a first terminal, and a second terminal, wherein the control terminal of the third transistor is configured to receive the third control potential, the first terminal of the third transistor is coupled to the ground potential, and the second terminal of the third transistor is coupled to the fifth node.

9. The power supply of claim 8, wherein the controller enables the third transistor when the switching potential rises to a second threshold potential higher than a first threshold potential.