TWM629645U - 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, an output resistor coupled to a voltage output end, and a voltage output pin coupled to the output resistor. The power supply circuit further has a plurality of equivalent resistance adjustment pins, each of which is coupled to the voltage output terminal through a resistance adjustment element. After an external capacitor is coupled to the voltage output pin, the output resistor, a plurality of the resistance adjustment elements and a line resistance between the voltage output pin and the external capacitor together 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 a 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, wherein the low dropout linear regulator includes: an operational amplifier 31a, a P-type MOS transistor 32a, including a first voltage dividing resistor A feedback unit of R1a and a second voltage dividing resistor 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 the equivalent series resistance (ESR) of the external capacitor C La can affect the low dropout linear regulator. Perform 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 of the low dropout linear regulator, 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 the 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, an output resistor coupled to a voltage output end of the low dropout linear regulator, and the output resistor coupled to the a voltage output pin; it is characterized in that the power supply circuit further has a plurality of equivalent resistance adjustment pins, and each of the equivalent resistance adjustment pins is coupled to the low dropout linear voltage regulator through a resistance adjustment element the voltage output of the device. 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 output resistance, a plurality of the resistance adjustment elements and the line resistance are formed together an equivalent resistance. With this design, even if the power supply circuit is applied in different electronic products and the resistance value of the line resistance varies from 0.1 ohm to 0.9 ohm, the resistance value of the equivalent resistance can still be controlled from 0.9 ohm to 0.9 ohm The change between 1.1 ohms can ensure the stability of the negative feedback loop of the operational amplifier of the power supply circuit and at the same time 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, an output resistor coupled to a voltage output end of the low dropout linear regulator, and a A voltage output pin of the output resistor; characterized in that the power supply circuit further has a plurality of equivalent resistance adjustment pins and a plurality of resistance adjustment elements, wherein each of the equivalent resistance adjustment pins is adjusted by at least one resistor The element is coupled to the voltage output terminal of the low dropout linear regulator.

In one embodiment, the resistance adjusting element is a passive element selected from the group consisting of metal resistors and polysilicon resistors.

In one embodiment, the resistance value of the resistance adjustment element is between 0.2 ohm and 0.8 ohm, and each of the resistance adjustment elements has different resistance values.

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 output resistor, a plurality of the resistance adjustment elements Together with the line resistance, an equivalent resistance is formed.

In another embodiment, after an external capacitor is coupled to one of the equivalent resistance adjustment pins, there is a line resistance between the equivalent resistance adjustment pin and the external capacitor, and the line resistance, a plurality of The resistance adjustment element and the output resistance together form 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 a feasible embodiment, at least two of the plurality of equivalent resistance adjustment pins are coupled to each other.

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 the present 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, in addition to having an output resistor coupled to a voltage output end of the low dropout linear regulator and a voltage output pin coupled to the output resistor, the present invention makes the power supply circuit further have a plurality of etc. Effective resistance adjustment pins, wherein each of the equivalent resistance adjustment pins is coupled to the voltage output end through a resistance adjustment element. In this way, when the power supply circuit is applied to different electronic devices, an external capacitor can be coupled to the voltage output pin or an equivalent resistance adjustment pin according to compensation requirements, so as to utilize the The resistance adjustment element compensates (adjusts) a line (parasitic) resistance between the external capacitor and the voltage output pin. According to this design, even if the power supply circuit is applied in different electronic products and the resistance value of the line resistance varies between 0.1 ohm and 0.9 ohm, the output resistance, a plurality of the resistance adjustment elements and the The equivalent resistance formed by the line resistance can still be controlled to vary between 0.9 ohms and 1.1 ohms, thereby ensuring the stability of the negative feedback loop of the power supply circuit and ensuring that the output voltage signal of the power supply circuit does not appear. glitch.

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 regulator (LDO) 30 , and the LDO 30 includes: an operational amplifier 31 , a P-type MOS circuit The crystal 32, a feedback unit including a first voltage dividing resistor R1 and a second voltage dividing resistor R2, and an output resistor R3. 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, and the output resistor R3 is coupled to the low dropout linear stabilizer between a voltage output terminal of the voltage regulator and the voltage output pin 33 . In particular, in the present invention, the power supply circuit 3 further includes a plurality of equivalent resistance adjustment pins 34-35, wherein each of the equivalent resistance adjustment pins R32-R33 is coupled to the other through a resistance adjustment element R _M1 -R _M2 . the voltage output terminal of the low dropout linear regulator 30 .

When the chip of the power supply circuit 3 of the present invention is fabricated by an integrated circuit process, the resistance adjustment elements R _M1 -R _M2 may be metal resistors or polysilicon resistors. Moreover, in one embodiment, the resistance value of the resistance adjustment element is between 0.2 ohm and 0.8 ohm, and each of the resistance adjustment elements R _M1 -R _M2 has different resistance values. For example, the power supply circuit 3 includes four resistance adjustment elements R _M1 -R _M4 in total, and the resistance values of the four resistance adjustment elements R _M1 -R _M4 may be 0.2Ω, 0.4Ω, 0.6Ω, and 0.8Ω, respectively.

When applying a power management chip or a power supply chip including the power supply circuit 3 , 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 0.1~1Ω. Because the present invention specifically makes the power supply circuit 3 further include a plurality of the equivalent resistance adjusting pins 34-35 and a plurality of the resistance adjusting elements R _M1 -R _M2 , therefore, as shown in FIG. 5, the external capacitor C After _L is coupled to the voltage output pin 33 , the output resistor R3 , a plurality of the resistance adjusting elements R _{M1 ˜R M2} and the line resistor R4 together form an equivalent resistor. At this time, since the resistance values of the resistance adjustment elements R _{M1 ˜R M2} are between 0.2 ohms to 0.8 ohms, even in different applications, the resistance value of the line resistor R4 is set between 0.1 ohms and 0.9 ohms. The resistance value of the equivalent resistance is still controlled to vary between 0.9 ohms and 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 utilizes a plurality of the resistance adjustment elements R _{M1 ˜R M2} , the output resistance R3 and the line resistance R4 to form an equivalent resistance together. 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 (that is, the variation of the resistance value is as high as 0.8 ohm), the resistance value of the equivalent resistance can still be controlled at 0.9 ohm to 1.1 ohms, that is, the change in the resistance value is adjusted to a range below 0.2Ω. 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.

FIG. 7 is a circuit topology structure diagram of a high-stability power supply circuit created by the present invention. As shown in FIG. 7 , when different electronic products or chip packaging methods are changed, the external capacitor _CL can also be selected to be coupled to one of the equivalent resistance adjustment pins 34 . At this time, the equivalent resistance adjustment pins There is a line resistance R4 between 34 and the external capacitor _CL , and the line resistance R4, a plurality of the resistance adjustment elements _{RM1 ˜RM2 and} the output resistance R3 together form an equivalent resistance. Simply put, the line resistance R4 will change as the application scheme changes. At this time, the external capacitor _CL can be selected to be coupled to an equivalent resistance adjustment pin 34 instead of the customary voltage output pin 33. .

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 , when different electronic products or chip packaging methods are changed, an external capacitor _CL can be coupled to the voltage output pin 33 , and at the same time, a plurality of the equivalent resistance adjustment pins 34 can be connected. At least two of ~35 are coupled to each other, so that the variation of the resistance value can be further reduced, and the stability of the negative feedback loop can be improved.

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, an output resistor coupled to a voltage output end of the low-dropout linear regulator, and an output resistor coupled to the output resistor a voltage output pin; characterized in that the power supply circuit further has a plurality of equivalent resistance adjustment pins, and each of the equivalent resistance adjustment pins is coupled to the low-dropout linear regulator through a resistance adjustment element of this voltage output. 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 output resistance, a plurality of the resistance adjustment elements and the line resistance are formed together an equivalent resistance. With this design, even if the power supply circuit is used in different electronic products and the resistance value of the line resistance varies from 0.1 ohm to 0.9 ohm, the resistance value of the equivalent resistance can still be controlled from 0.9 ohm to 0.9 ohm The change between 1.1 ohms can ensure the stability of the negative feedback loop of the operational amplifier of the power supply circuit and at the same time 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 supply chip 31a: Operational amplifier 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: No. 1 Two voltage divider resistor R3a: Output resistor R4a: Line resistance C _La : External capacitor 3: Power supply circuit 30: Low dropout linear regulator 31: Operational amplifier 32: P-type MOS transistor 33: Voltage output pin 34: Equivalent Resistance adjustment pin 35: Equivalent resistance adjustment pin R1: First voltage dividing resistor R2: Second voltage dividing resistor R3: Output resistor R4: Line resistance RM1: Resistance adjustment element RM2: Resistance adjustment element _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; FIG. 7 is a circuit topology diagram of a high-stability power supply circuit of the present creation; and FIG. 8 is a circuit topology structure diagram of a high-stability power supply circuit created by 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: Equivalent resistance adjustment pin

35: Equivalent resistance adjustment pin

R1: The first voltage divider resistor

R2: The second voltage divider resistor

R3: output resistance

R4: Line resistance

R _M1 : Resistance adjustment element

R _M2 : Resistance adjustment element

C _L : External capacitor

Claims (10)

A power supply circuit has at least one low dropout linear regulator, an output resistor coupled to a voltage output end of the low dropout linear regulator, and a voltage output pin coupled to the output resistor; it is characterized in that , the power supply circuit further has a plurality of equivalent resistance adjustment pins and a plurality of resistance adjustment elements, wherein each of the equivalent resistance adjustment pins is coupled to the low dropout linear regulator through at least one resistance adjustment element. voltage output. The power supply circuit of claim 1, wherein the resistance adjusting element is a passive element selected from the group consisting of metal resistors and polysilicon resistors. The power supply circuit of claim 2, wherein the resistance value of the resistance adjustment element is between 0.2 ohm and 0.8 ohm, and each of the resistance adjustment elements has different resistance values. The power supply circuit of claim 2, 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. At this time, the output resistance, the complex number Each of the resistance adjustment elements and the line resistance together constitute an equivalent resistance. The power supply circuit of claim 2, wherein after an external capacitor is coupled to one of the equivalent resistance adjustment pins, there is a line resistance between the equivalent resistance adjustment pins and the external capacitor, and the The line resistance, a plurality of the resistance adjustment elements and the output resistance together form an equivalent resistance. The power supply circuit according to claim 4 or 5, 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 is correspondingly between 0.9 ohm and 1.1 ohm. change between. The power supply circuit of claim 2, wherein at least two of the plurality of equivalent resistance adjustment pins are coupled to each other. 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 7. An information processing device comprising at least one power management chip as described in claim 8. The information processing device according to claim 9, 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 An electronic device in the group consisting of computers, and industrial computers.

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