TWM630503U - High stability power supply circuit, power management chip and information processing device - Google Patents

Abstract

The present invention mainly discloses a power supply circuit with high stability, which has at least one low dropout linear regulator and a voltage output pin coupled to a voltage output end of the low dropout linear regulator. The power supply circuit further has a resistance adjustable unit and a control unit, the resistance adjustable unit is coupled between the voltage output terminal and the voltage output pin, and changes its resistance value according to a control signal of the control unit. After an external capacitor is coupled to the voltage output pin, the resistance adjustable unit and a line resistance between the voltage output pin and the external capacitor form an equivalent resistance. According to this design, even if the power supply circuit is used in different electronic products and the resistance value of the line resistance varies between 0.1 ohm and 0.9 ohm, the resistance value of the equivalent resistance can still be controlled between 0.9 ohm and 1.1 ohm. between ohms, so as to ensure the stability of the negative feedback loop and ensure that the output voltage signal does not appear glitches.

Description

High stability power supply circuit, power management chip and information processing device

This creation relates to the technical field of electronic circuits, especially to a high-stability power supply circuit for realizing power management of information processing devices.

It should be known that an electronic product includes a power supply device (eg, a lithium battery) for providing suitable driving power to various chips and electronic components inside. However, since the driving power (ie, operating voltage) required by different chips and electronic components will be different, the existing electronic products also include a power management chip for converting the power output from the lithium battery after a power conversion process. , and then provide suitable driving power to the corresponding chips and electronic components.

FIG. 1 shows a structure diagram of a conventional display device of a smart phone. At present, the display screen of the smart phone has been developed towards a full-screen design, so that the display driver chip 1a including the gate driver circuit and the source driver circuit and the power supply including at least one low-dropout regulator (LDO) The chip 3a must be integrated with the display panel 4a by COF technology. The COF is Chip On Film, which is used to integrate the display driver chip 1a and the power supply chip 3a on a COF circuit board 5a. Further, as shown in FIG. 1 , the COF circuit board 5a is coupled to a flexible printed circuit (FPC) 6a, so as to be coupled to the main board inside the smartphone through the flexible printed circuit 6a.

FIG. 2 shows a circuit topology diagram of a conventional power supply chip 3a including at least one low dropout linear regulator. As shown in FIG. 2, the power supply chip 3a includes at least one low-dropout linear regulator 30a, wherein the low-dropout linear regulator 30a includes: an operational amplifier 31a, a P-type MOS transistor 32a, including a first A feedback unit of a piezoresistor R1a and a second piezoresistor R2a, and an output resistor R3a. It is worth noting that, when the power supply chip 3a is applied, an external capacitor C _La is usually connected in series with a voltage output pin 33a of the power supply chip 3a, and there is an external capacitor C _La and the voltage output pin 33a between the external capacitor C La and the voltage output pin 33a. A line resistance R4a. At this time, the output voltage of the low dropout linear regulator V _Y =V _REF *(R _1a +R _2a )/R _2a . Electronic engineers who are familiar with the design and manufacture of smart phones should know that the capacitance value of the external capacitor C _La is about 1 μF, and its own equivalent series resistance (ESR) can affect the low dropout linear regulator. 30a performs frequency compensation. Unfortunately, the ESR value of the external capacitor C _La cannot be precisely controlled. For example, ceramic capacitors have a low ESR of about 10mΩ, while tantalum capacitors have an ESR of about 100mΩ. In addition, when applied to different electronic products, such as tablet computers, the packaging method of the power supply chip 3a will also be different, resulting in the voltage output pin 33a of the power supply chip 3a to the external capacitor C _La . The resistance value of the line resistance R4a will also change accordingly, and the change range is about 0.1~1Ω.

………………………(a) Therefore, in order to stabilize the output voltage V _Y of the low dropout linear regulator 30a, it is necessary to ensure the stability of the negative feedback loop of the operational amplifier 31a. FIG. 2 shows a complex plane diagram of the negative feedback loop of operational amplifier 31a. Among them, the Y point marked in Figure 1 corresponds to the main pole p1 marked in Figure 2, the X point corresponds to the secondary pole p2, and the output resistance R3a, the line resistance R4a and the external capacitor C _La form a left half plane of the complex plane. Zero point z1. Therefore, the zero point z1 can be calculated by the following formula (a).

……………………(a)

FIG. 3 is a Bode plot of the power supply chip 3a of FIG. 2 having at least one low dropout linear regulator. Among them, the gain-frequency diagram in the Bode plot shows that when the resistance value of R3a+R4a is small, the zero point z1 is much larger than the secondary pole p2, resulting in the phase in the Bode diagram ( phase) ^-frequency plot showing a phase margin (PM) of less than 45o. In this case, the phase margin of the power supply chip 3a is insufficient.

FIG. 4 shows the operation timing diagram of the output voltage V _Y and a load current I _load of the power supply chip 3 a. In practical operation, increasing the resistance of R3a+R4a can achieve acceptable frequency compensation and improve the phase margin of the power supply chip 3a. Unfortunately, as shown in FIG. 4, when the load current I _load increases or decreases instantaneously, a burr will appear on the signal of the output voltage V _Y output by the power supply chip 3a, wherein the amplitude of the burr and (R _3a +R _4a )*I _load is correlated.

As can be seen from the above description, since the power supply chip 3a will be applied to different electronic products, the type of the external capacitor C _La and the line resistance R between the voltage output pin 33a of the power supply chip 3a and the external capacitor C _{La 4a} will be changed accordingly, making it difficult to simultaneously ensure the stability of the negative feedback loop of the operational amplifier 31a and ensure that no glitches appear on the output voltage signal.

It can be seen from the above description that there is an urgent need in the art for a power supply circuit with high stability.

The main purpose of the present invention is to provide a high stability power supply circuit, which has at least one low dropout linear regulator and a voltage output pin coupled to a voltage output end of the low dropout linear regulator. The power supply circuit further has a resistance adjustable unit and a control unit, the resistance adjustable unit is coupled between the voltage output terminal and the voltage output pin, and changes its resistance value according to a control signal of the control unit. After an external capacitor is coupled to the voltage output pin, the resistance adjustable unit and a line resistance between the voltage output pin and the external capacitor form an equivalent resistance. According to this design, even if the power supply circuit is used in different electronic products and the resistance value of the line resistance varies between 0.1 ohm and 0.9 ohm, the resistance value of the equivalent resistance can still be controlled between 0.9 ohm and 1.1 ohm. between ohms, so as to ensure the stability of the negative feedback loop and ensure that the output voltage signal does not appear glitches.

In order to achieve the above object, the present invention proposes an embodiment of the power supply circuit, which has at least one low dropout linear regulator and a voltage output pin coupled to a voltage output end of the low dropout linear regulator; which It is characterized in that the power supply circuit further has a resistance adjustable unit and a control unit, the resistance adjustable unit has a first end coupled to the voltage output terminal, a second end coupled to the voltage output pin, and a coupling A control terminal connected to a control signal sent by the control unit.

In one embodiment, after an external capacitor is coupled to the voltage output pin, there is a line resistance between the voltage output pin and the external capacitor. At this time, the resistance adjustable unit and the line resistance are formed together. an equivalent resistance.

In one embodiment, when the resistance value of the line resistor varies from 0.1 ohm to 0.9 ohm, the resistance value of the equivalent resistor varies from 0.9 ohm to 1.1 ohm correspondingly.

In one embodiment, the adjustable resistance unit includes a group selected from the group consisting of a P-type MOSFET element, an N-type MOSFET element, and a CMOS unit formed by connecting a P-type MOSFET element and an N-type MOSFET element. a switching element in .

In another embodiment, the control unit is a functional electronic unit selected from the group consisting of digital-to-analog converters and registers.

In one embodiment, the adjustable resistance unit includes:

a resistive element having a first end coupled to the voltage output end and a second end coupled to the voltage output pin; and

A switch element has a first end, a second end and a control end, wherein the first end is coupled to the voltage output end, the second end is coupled to the voltage output pin, and the control end is coupled to the voltage output pin The control signal transmitted by the control unit.

In another embodiment, the adjustable resistance unit includes:

a resistive element having a first end coupled to the voltage output end and a second end coupled to the voltage output pin; and

A plurality of switching elements, wherein each of the switching elements has a first terminal, a second terminal and a control terminal, and the first terminal of each of the switching elements is coupled to the voltage output terminal, so as to The second end is coupled to the voltage output pin, and the control end is coupled to the control signal sent by the control unit.

In yet another embodiment, the adjustable resistance unit includes:

a first switch element having a first end coupled to the voltage output end, a second end coupled to the voltage output pin, and a control end coupled to the control signal sent by the control unit; and

A plurality of second switching elements, wherein each of the second switching elements has a first terminal, a second terminal and a control terminal, and each of the second switching elements is coupled with its first terminal The voltage output terminal, the second terminal thereof is coupled to the voltage output pin, and the control terminal thereof is coupled to the control signal transmitted by the control unit.

The present invention also provides a power management chip, characterized in that, the power management chip includes the power supply circuit of the present invention as described above.

The present invention also provides an information processing device comprising at least one power management chip of the present invention as described above. In one embodiment, the information processing device is selected from the group consisting of smart phones, smart watches, smart bracelets, tablet computers, notebook computers, all-in-one computers, access control devices, desktop computers, and industrial computers. An electronic device in a group.

In order to enable your reviewers to further understand the structure, features, purposes, and advantages of this creation, drawings and detailed descriptions of preferred specific embodiments are attached as follows.

The present invention proposes a high stability power supply circuit including at least one low dropout linear voltage regulator. It is characterized in that, the present invention makes the power supply circuit further have a resistance adjustable unit and a control unit, the resistance adjustable unit is coupled to the voltage output end of the low dropout linear regulator and the voltage output pin of the power supply circuit between bits. When the power supply circuit is applied to different electronic devices, an external capacitor can be coupled to the voltage output pin according to compensation requirements, and the resistance value of the resistance adjustable unit can be adjusted by the control unit, so that the voltage A line (parasitic) resistance between the output pin and the external capacitor together with the resistance adjustable unit constitutes an equivalent resistance. According to this design, even if the power supply circuit is used in different electronic products and the resistance value of the line resistance varies between 0.1 ohm and 0.9 ohm, the resistance value of the equivalent resistance can still be controlled between 0.9 ohm and 1.1 ohm. between ohms, so as to ensure the stability of the negative feedback loop and ensure that the output voltage signal does not appear glitches.

FIG. 5 is a circuit topology structure diagram of a high-stability power supply circuit created by the present invention. As shown in FIG. 5 , the power supply circuit 3 includes at least one low-dropout linear regulator (LDO) 30 , and the low-dropout linear regulator 30 mainly includes: an operational amplifier 31 , a P-type MOS The transistor 32, and a feedback unit including a first voltage dividing resistor R1 and a second voltage dividing resistor R2. The power supply circuit 3 of the present invention is mainly included in a power management chip or a (DC) power supply chip, so the chip itself has at least one voltage output pin 33 . As shown in FIG. 5, the present invention specifically makes the power supply circuit 3 further include: a resistance adjustable unit 34 and a control unit 35, wherein the resistance adjustable unit 34 has a first end coupled to the voltage output end, a Connect to a second end of the voltage output pin 33 and a control end, and the control unit 35 is used to generate a control signal and transmit it to the control end of the resistance adjustable unit 34, so that the resistance can be adjusted or changed. The resistance value of the unit 34 is adjusted.

When a power management chip or a power supply chip including the power supply circuit 3 is applied, an external capacitor _CL is usually connected in series with the voltage output pin 33 . It should be known that when applied to different electronic products, such as smart phones, tablet computers, flat panel displays, etc., the chip packaging method will also be different, resulting in the voltage output pin 33 to the external capacitor _CL The resistance value of a line resistance R4 between them will also change accordingly, and the change range is about 0.1~0.9Ω. Therefore, the resistance value of the adjustable resistance unit 34 can be adjusted by the control unit 35, so that an equivalent resistance of the adjustable resistance unit 34 and the line resistance R4 is controlled to be about 1 ohm. In this way, even if the resistance value of the line resistor R4 is changed between 0.1 ohm and 0.9 ohm in different applications, the resistance value of the equivalent resistor can still be controlled to vary between 0.8 ohm and 1.2 ohm, and even be controlled between 0.8 ohm and 1.2 ohm. Varies from 0.9 ohms to 1.1 ohms.

Please refer to FIG. 3 and FIG. 5 repeatedly, wherein the Y point indicated in FIG. 5 corresponds to the main pole p1 indicated in FIG. 3 , the X point corresponds to the secondary pole p2 , and the output resistor R3 , the line resistor R4 and the external capacitor C _L forms a zero point z1 corresponding to that indicated in FIG. 3 . FIG. 6 is a Bode plot of the power supply circuit of FIG. 5 having at least one low dropout linear regulator. In practical operation, increasing the resistance value of R3+R4 has the opportunity to achieve acceptable frequency compensation and improve the phase margin (PM) of the low dropout linear regulator 30 . Unfortunately, as shown in FIG. 4, when the load current I _load increases or decreases instantaneously, a burr will appear on the output voltage signal output by the low dropout linear regulator 30, wherein the amplitude of the burr and ( R ₃ +R ₄ )*I _load is correlated. Therefore, the present invention uses the control unit 35 to adjust the resistance value of the adjustable resistance unit 34, so that the equivalent resistance of the adjustable resistance unit 34 and the line resistance R4 is controlled to vary between 0.9 ohms and 1.1 ohms in different applications .

In different applications, the resistance value of the line resistor R4 may vary from 0.1 ohm to 0.9 ohm (ie, the variation of the variable resistance value is as high as 0.8 Ω). However, after adjusting the resistance adjustable unit 34 with the control unit 35 In the case of the resistance value, the equivalent resistance of the resistance adjustable unit 34 and the line resistance R4 can be controlled to vary between 0.9 ohms and 1.1 ohms, that is, the resistance value variation is effectively reduced to less than 0.2 Ω range. According to this design, as shown in FIG. 6, there is an opportunity to adjust the zero point z1 to make it re-sum with the secondary pole p2, that is, the zero point z1 is used to compensate the pole, thereby greatly improving the phase margin of the low dropout linear regulator 30, achieving Ideal compensation. In this way, the stability of the negative feedback loop of the power supply circuit can be ensured, and at the same time, the output voltage signal of the power supply circuit can be guaranteed not to have glitches.

7A, 7B and 7C respectively show circuit diagrams of an N-type MOSFET element, a P-type MOSFET element and a CMOS switch unit. In a feasible embodiment, the resistance adjustable unit 34 can be an N-type MOSFET element as shown in FIG. 7A , a P-type MOSFET element as shown in FIG. 7B , or a CMOS switch unit as shown in FIG. 7C , wherein the The CMOS switch unit is mainly formed by connecting one of the N-type MOSFET elements and one of the P-type MOSFET elements.

FIG. 8 is a circuit topology structure diagram of a high-stability power supply circuit created by the present invention. As shown in FIG. 8 , in another embodiment, the adjustable resistance unit 34 can be designed to include a resistance element 341 and a first switch element 342 . The resistance element 341 has a first end coupled to the voltage output end and a second end coupled to the voltage output pin 33 . When the chip of the power supply circuit 3 of the present invention is fabricated by an integrated circuit process, the resistive element 341 may be a metal resistor or a polysilicon resistor. On the other hand, the first switch element 342 has a first terminal, a second terminal and a control terminal, wherein the first terminal is coupled to the voltage output terminal, and the second terminal is coupled to the voltage output pin 33 , And the control end is coupled to the control signal sent by the control unit 35 . In this embodiment, as shown in FIG. 8 , the control unit 35 includes a digital-to-analog converter 351 for generating a digital signal to generate the control signal to control the first switching element 342 (ie, the N-type MOSFET). component) channel resistance.

FIG. 9 is a circuit topology structure diagram of a high-stability power supply circuit created by the present invention. As shown in FIG. 9 , in another embodiment, the adjustable resistance unit 34 can be designed to include: a resistance element 341 and N−1 second switching elements 343 . The resistance element 341 has a first end coupled to the voltage output end and a second end coupled to the voltage output pin 33 . On the other hand, each of the second switching elements 343 has a first terminal, a second terminal and a control terminal, and the first terminal of each of the second switching elements 343 is coupled to the voltage output The second terminal is coupled to the voltage output pin 33 , and the control terminal is coupled to the control signal sent by the control unit 35 . In this embodiment, as shown in FIG. 9 , the control unit 35 includes a register 352 , which outputs a digitized control signal S<1:n-1> to N-1 according to the control of the control unit 35 . The control terminal of the second switching element 343 (ie, the N-type MOSFET element) is used to adjust the channel resistance of each second switching element 343 .

FIG. 10 is a circuit topology structure diagram of a high-stability power supply circuit of the present invention. As shown in FIG. 10 , in another possible embodiment, the resistance adjustable unit 34 can be designed to include: a first switch element 342 and N−1 second switch elements 343 . The first switch element 342 has a first end coupled to the voltage output end, a second end coupled to the voltage output pin 33 and a control end coupled to the control signal sent by the control unit 35 . On the other hand, each of the second switching elements 343 has a first terminal, a second terminal and a control terminal, and the first terminal of each of the second switching elements 343 is coupled to the voltage output The second terminal is coupled to the voltage output pin 33 , and the control terminal is coupled to the control signal sent by the control unit 35 . In this embodiment, as shown in FIG. 10 , the control unit 35 includes a register 352 , which outputs a digitized control signal S<1:n> to the first switch element 342 ( That is, an N-type MOSFET element) and the control terminals of the N−1 second switching elements 343 (ie, an N-type MOSFET element), so as to regulate the channel resistance of each N-type MOSFET element.

In this way, the above has completely and clearly described a high-stability power supply circuit of the present invention; and, from the above, it can be known that the present invention has the following advantages:

(1) The present invention discloses a high stability power supply circuit, which has at least one low dropout linear regulator and a voltage output pin coupled to a voltage output end of the low dropout linear regulator. The power supply circuit further has a resistance adjustable unit and a control unit, the resistance adjustable unit is coupled between the voltage output terminal and the voltage output pin, and changes its resistance value according to a control signal of the control unit. After an external capacitor is coupled to the voltage output pin, the resistance adjustable unit and a line resistance between the voltage output pin and the external capacitor form an equivalent resistance. According to this design, even if the power supply circuit is used in different electronic products and the resistance value of the line resistance varies between 0.1 ohms and 0.9 ohms, the resistance value of the equivalent resistance can still be controlled between 0.9 ohms and 1.1 ohms. between ohms, so as to ensure the stability of the negative feedback loop and ensure that the output voltage signal does not appear glitches.

(2) The present invention also provides a power management chip, characterized in that, the power management chip includes the power supply circuit of the present invention as described above.

(3) The present invention also provides an information processing device comprising at least one power management chip of the present invention as described above. Wherein, the information processing device is selected from the group consisting of smart phones, smart watches, smart bracelets, tablet computers, notebook computers, all-in-one computers, access control devices, desktop computers, and industrial computers of an electronic device.

It must be emphasized that the above-mentioned disclosure in this case is a preferred embodiment, and any partial changes or modifications originating from the technical ideas of this case and easily inferred by those who are familiar with the art are within the scope of the patent of this case. category of rights.

In summary, regardless of the purpose, means and effect of this case, it shows that it is completely different from the conventional technology, and its first creation is suitable for practical use, and it does meet the requirements of a new type of patent. Society is to pray for the best.

1a: Display driver chip 3a: Power chip 31a: Operational amplifier 30a: Low dropout linear regulator 32a: P-type MOS transistor 33a: Voltage output pin 4a: Display panel 5a: COF circuit board 6a: Flexible circuit board R1a: First voltage dividing resistor R2a: Second voltage dividing resistor R3a: Output resistor R4a: Line resistance C _L a: External capacitor 3: Power supply circuit 30: Low dropout linear regulator 31: Operational amplifier 32: P-type MOS transistor 33 : voltage output pin 34: adjustable resistance unit 341: resistance element 342: first switching element 343: second switching element 35: control unit 351: digital-to-analog converter 352: register R1: first voltage dividing resistor R2: first Two voltage divider resistor R4: line resistance _CL : external capacitor

FIG. 1 is a schematic diagram of a display device of a conventional smart phone; 2 is a circuit topology diagram of a conventional power supply chip including at least one low dropout linear voltage regulator; 3 is a Bode plot of the power supply chip of FIG. 2 having at least one low dropout linear regulator; FIG. 4 is a working timing diagram of an output voltage and a load current of the power supply chip of FIG. 2; Figure 5 is a circuit topology structure diagram of a high-stability power supply circuit created by the present invention; 6 is a Bode plot of the power supply circuit of FIG. 5 having at least one low dropout linear regulator; 7A, 7B and 7C respectively show circuit diagrams of an N-type MOSFET element, a P-type MOSFET element and a CMOS switch unit; FIG. 8 is a circuit topology structure diagram of a high-stability power supply circuit created by the present invention; FIG. 9 is a circuit topology structure diagram of a high-stability power supply circuit of the present creation; and FIG. 10 is a circuit topology structure diagram of a high-stability power supply circuit of the present invention.

3: Power supply circuit

30: Low dropout linear regulator

31: Operational Amplifier

32: P-type MOS transistor

33: Voltage output pin

34: Resistance adjustable unit

35: Control unit

R1: The first voltage divider resistor

R2: The second voltage divider resistor

R4: Line resistance

C _L : External capacitor

Claims (10)

A power supply circuit has at least one low dropout linear regulator and a voltage output pin coupled to a voltage output end of the low dropout linear regulator; it is characterized in that the power supply circuit further has an adjustable resistance unit and a control unit, the resistance adjustable unit has a first end coupled to the voltage output end, a second end coupled to the voltage output pin, and a control unit coupled to a control signal sent by the control unit end. The power supply circuit of claim 1, wherein after an external capacitor is coupled to the voltage output pin, there is a line resistance between the voltage output pin and the external capacitor, and the resistance adjustable unit and The line resistances together constitute an equivalent resistance. The power supply circuit as claimed in claim 2, wherein when the resistance value of the line resistance varies between 0.1 ohm and 0.9 ohm, the resistance value of the equivalent resistor varies between 0.9 ohm and 1.1 ohm correspondingly . The power supply circuit according to claim 1, wherein the adjustable resistance unit comprises a CMOS selected from a P-type MOSFET element, an N-type MOSFET element, and a P-type MOSFET element connected to an N-type MOSFET element A switch element in a group of cells. The power supply circuit of claim 1, wherein the control unit is a functional electronic unit selected from the group consisting of a digital-to-analog converter and a register. The power supply circuit of claim 1, wherein the adjustable resistance unit comprises: a resistive element having a first end coupled to the voltage output end and a second end coupled to the voltage output pin; and A switch element has a first end, a second end and a control end, wherein the first end is coupled to the voltage output end, the second end is coupled to the voltage output pin, and the control end is coupled to the voltage output pin The control signal transmitted by the control unit. The power supply circuit of claim 1, wherein the adjustable resistance unit comprises: a resistive element having a first end coupled to the voltage output end and a second end coupled to the voltage output pin; and A plurality of switching elements, wherein each of the switching elements has a first terminal, a second terminal and a control terminal, and the first terminal of each of the switching elements is coupled to the voltage output terminal, so as to The second end is coupled to the voltage output pin, and the control end is coupled to the control signal sent by the control unit. The power supply circuit of claim 1, wherein the adjustable resistance unit comprises: a first switch element having a first end coupled to the voltage output end, a second end coupled to the voltage output pin, and a control end coupled to the control signal sent by the control unit; and A plurality of second switching elements, wherein each of the second switching elements has a first terminal, a second terminal and a control terminal, and each of the second switching elements is coupled with its first terminal The voltage output terminal, the second terminal thereof is coupled to the voltage output pin, and the control terminal thereof is coupled to the control signal transmitted by the control unit. A power management chip, characterized in that the power management chip includes the power supply circuit described in any one of claim 1 to claim 8. An information processing device comprising at least one power management chip as claimed in claim 9.

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