Wide input voltage range startup circuit and power manager

Abstract

This application discloses a startup circuit and power manager with a wide input voltage range, applicable to the field of integrated circuit technology. The startup circuit includes: an auxiliary protection unit, a first current-limiting resistor, a high-voltage startup path unit, and a low-voltage startup path unit. The first current-limiting resistor provides the auxiliary protection unit and the high-voltage startup path unit with the required operating current. The auxiliary protection unit, under the action of the operating current, generates a first clamping protection voltage and a second clamping protection voltage to control the high-voltage startup path unit or the low-voltage startup path unit at different input voltages, thereby establishing a corresponding output voltage for the input voltage. By recycling the current-limiting current at high input voltage in the high-voltage startup path unit, the goals of low power consumption, a wide input voltage range, and a smaller integrated circuit layout area are achieved.

Description

Technical Field

[0001] The present application relates to the technical field of integrated circuits, and in particular to a startup circuit and a power manager with a wide input voltage range. Background Art

[0002] For switching power supplies, such as DC-DC power converters, a startup circuit is usually provided. Figure 1 As shown in Figure 1, traditional startup circuits often use a simple current-limiting resistor R0 and a clamping diode Z0 in series to form a clamping branch. This provides startup control for the load (such as transistor NM0) during the power-up process of the input voltage Vin, ensuring that the input voltage Vin provides stable and reliable power to the load during the load power-up process. Although the startup circuit has a simple structure, as new application requirements for chips such as low power consumption and a wide input voltage range are being introduced, its performance cannot meet these application requirements due to its inherent limitations.

[0003] Based on this, a new startup circuit technology solution with low power consumption and wide input voltage range is needed. Summary of the Invention

[0004] In view of this, embodiments of the present disclosure provide a startup circuit and a power manager with a wide input voltage range, achieving the integrated circuit design goals of low power consumption, a wide input voltage range, and a smaller chip layout area.

[0005] The embodiments of this specification provide the following technical solutions:

[0006] The embodiment of this specification provides a startup circuit with a wide input voltage range, comprising: an auxiliary protection unit, a first current limiting resistor, a high-voltage startup path unit, and a low-voltage startup path unit;

[0007] The first end of the first current limiting resistor is connected to the input voltage, and the second end of the first current limiting resistor is connected to the auxiliary protection unit and the high-voltage startup path unit respectively, so as to provide the auxiliary protection unit and the high-voltage startup path unit with the working current required for operation;

[0008] The auxiliary protection unit is used to form a first clamping protection voltage and a second clamping protection voltage under the action of the working current, and output the first clamping protection voltage to the high-voltage startup path unit, and output the second clamping protection voltage to the low-voltage startup path unit;

[0009] When the input voltage is a voltage higher than a first threshold, the difference between the first clamping protection voltage and the second clamping protection voltage formed by the auxiliary protection unit is greater than a second threshold, so that the high-voltage startup path unit establishes a corresponding output voltage for the input voltage under the control of the first clamping protection voltage; and when the input voltage is a voltage not higher than the first threshold, the difference between the first clamping protection voltage and the second clamping protection voltage formed by the auxiliary protection unit is not greater than the second threshold, so that the low-voltage startup path unit establishes the corresponding output voltage for the input voltage under the control of the second clamping protection voltage.

[0010] Compared with the prior art, the at least one technical solution adopted in the embodiments of this specification can achieve the following beneficial effects:

[0011] The low-power dual-channel high-voltage startup circuit has two paths for normal operation under two different extreme conditions of low input voltage and high input voltage, meeting the power supply requirements of a wide input power supply voltage range;

[0012] The low-power dual-channel high-voltage startup circuit has lower power consumption. Compared with the useless current wasted in the current-limiting resistor path in the traditional step-down startup circuit, the present invention can utilize most of the current of the current-limiting resistor branch in the high-voltage startup path unit, greatly reducing the power consumption of the entire circuit;

[0013] The low-power dual-channel high-voltage startup circuit has a smaller area in the layout. This is because the present invention does not require a large-resistance current-limiting resistor for current limiting, so the area occupied by the step-down startup part in the layout is also greatly reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0015] Figure 1 It is a structural diagram of an existing starting circuit;

[0016] Figure 2 This is a schematic diagram of the structure of a startup circuit with a wide input voltage range in this application;

[0017] Figure 3 This is a schematic structural diagram of a startup circuit with a wide input voltage range in this application. DETAILED DESCRIPTION

[0018] The embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0019] The following describes the embodiments of the present application through specific examples, and those skilled in the art can easily understand other advantages and effects of the present application from the contents disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The present application can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that, in the absence of conflict, the features in the following embodiments and embodiments can be combined with each other. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of this application.

[0020] It should be noted that various aspects of the embodiments within the scope of the appended claims are described below. It should be apparent that the aspects described herein can be embodied in a wide variety of forms, and any specific structure and / or function described herein is merely illustrative. Based on this application, it should be understood by those skilled in the art that an aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number and aspect described herein can be used to implement an apparatus and / or practice a method. In addition, other structures and / or functionalities other than one or more of the aspects described herein can be used to implement this apparatus and / or practice this method.

[0021] It should also be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present application. The illustrations only show components related to the present application and are not drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component can be changed at will, and the component layout type may also be more complicated.

[0022] Additionally, in the following description, specific details are provided to provide a thorough understanding of the examples, however, one skilled in the art will appreciate that the examples can be practiced without these specific details.

[0023] As Figure 1 The conventional startup circuit shown, i.e., the clamping branch composed of R0 and the voltage regulator Z0, enables the voltage regulator Z0 to stably provide the clamping voltage, and enables the input voltage Vin to stably establish a corresponding voltage signal during the power-on process of the load switch NM0.

[0024] Although the structure of the startup circuit is simple, it is limited by the operating current of the voltage regulator Z0 and cannot meet application requirements such as low power consumption and a wide input voltage range.

[0025] For example, under high input voltage conditions, the current flowing through the current-limiting resistor R0 is relatively large. At this time, due to the operating current limit of the voltage-limiting diode Z0, the current-limiting resistor R0 needs to have a larger resistance value to ensure that the voltage-limiting diode Z0 operates within a safe range. However, a current-limiting resistor with a larger resistance value needs to occupy a larger resistor layout area in the integrated circuit. In addition, when a large current flows through the current-limiting resistor R0, the power consumption of the current-limiting resistor is large, and this part of the energy cannot be recycled and will be wasted, making it impossible to achieve low power consumption.

[0026] For example, if the value of the current limiting resistor is fixed, an input voltage that is too high or too low will cause the startup circuit to malfunction, limiting the range of the input voltage and failing to meet application requirements with a wide input voltage range.

[0027] In view of this, the inventor has conducted in-depth research and improved exploration on the power supply circuit and its starting circuit, and proposed a structural scheme of the starting circuit: Figure 2 As shown, the startup circuit is provided with two paths and protection units thereof, namely, an auxiliary protection unit 100 , a high-voltage startup path unit 200 and a low-voltage startup path unit 300 .

[0028] Specifically, a first end of the first current limiting resistor R1 is connected to the input voltage Vin, and a second end of the first current limiting resistor R1 is connected to the auxiliary protection unit 100 and the high-voltage startup path unit 200, respectively, to provide the auxiliary protection unit 100 and the high-voltage startup path unit 200 with the working current required for operation;

[0029] The auxiliary protection unit 100 is configured to generate a first clamping protection voltage V1 and a second clamping protection voltage V2 according to the operating current, and output the first clamping protection voltage V1 to the high-voltage startup path unit 200, and output the second clamping protection voltage V2 to the low-voltage startup path unit 300;

[0030] Among them, when the input voltage Vin is a voltage higher than a first threshold, the difference between the first clamping protection voltage V1 and the second clamping protection voltage V2 formed by the auxiliary protection unit 100 is greater than a second threshold, so that the high-voltage startup path unit 200 establishes a corresponding output voltage Vout for the input voltage Vin under the control of the first clamping protection voltage V1, and when the input voltage Vin is a voltage not higher than the first threshold, the difference between the first clamping protection voltage V1 and the second clamping protection voltage V2 formed by the auxiliary protection unit 100 is not greater than the second threshold, so that the low-voltage startup path unit 300 establishes the corresponding output voltage Vout for the input voltage Vin under the control of the second clamping protection voltage V2.

[0031] It should be noted that the first value used to distinguish whether the input voltage is high voltage or low voltage can be determined based on the actual application design and is not limited. Furthermore, the second threshold used to switch between the high-voltage startup path unit and the low-voltage startup path unit can be determined based on the dual-channel startup path switching requirements. Generally, the second threshold can be a positive value and is not specifically limited.

[0032] After adopting this circuit structure, the following significant technical effects can be achieved:

[0033] On the one hand, according to different input voltages Vin, for example, when the input voltage Vin is higher, the high-voltage startup path unit 200 works while the low-voltage startup path unit 300 does not work; for example, when the input voltage Vin is lower, the high-voltage startup path unit 200 does not work while the low-voltage startup path unit 300 works. This can adapt to a wide input voltage range, for example, an input voltage range of 3V to 80V, or even various input voltages such as below 3V and above 80V. It can still work normally, thereby being able to work normally under two different extreme conditions of low input voltage and high input voltage, meeting the power supply requirements of a wide input power supply voltage range;

[0034] Secondly, compared to the traditional step-down startup circuit, since the auxiliary protection unit 100 is only used to provide the clamping protection voltage, the required operating current is relatively small. Therefore, when the high voltage input voltage Vin is applied, even if the current flowing through the current-limiting resistor R1 is large, most of the branch current of this current will be used as the operating current of the high-voltage startup path unit. That is, most of the current in the current-limiting resistor branch is used in the high-voltage startup path unit and is recycled in the high-voltage startup path unit instead of being wasted, which greatly reduces the power consumption of the entire circuit.

[0035] Third, at a relatively low input voltage Vin (e.g., 3V), the current flowing through the current-limiting resistor R1 is very small. Even at a relatively high input voltage Vin (e.g., 80V), although the current flowing through the current-limiting resistor R1 is relatively large, most of the current is used as the operating current of the high-voltage startup path unit 200. Not only is the current not wasted, but the current-limiting resistor R1 does not need to use a large-value resistor for current limiting. Therefore, the current-limiting resistor occupies a relatively small area in the integrated circuit, which helps to reduce the layout area of ​​the step-down startup circuit.

[0036] Fourthly, the dual-channel startup circuit has a wide range of working environments. After PVT (Process Verification Test, small batch process verification test) verification, it can work stably under high and low voltage, high and low temperature and various process angle working conditions. At the same time, the circuit structure is simple and the reliability is high, ensuring that the startup circuit can safely and reliably establish a stable and safe output voltage for the input voltage during the power-on process.

[0037] It should be noted that the aforementioned first threshold value can be a voltage value determined according to actual application needs and is not limited here.

[0038] Furthermore, the high-voltage startup path unit and the low-voltage startup path unit may refer to circuit units that establish a corresponding output voltage Vout for the input voltage Vin after forming a path, such as a switch unit, a power conversion unit, etc.

[0039] In some embodiments, the startup path unit adopts a switch circuit, so the startup path unit is equivalent to a switch with a control terminal.

[0040] In implementation, the high-voltage startup path unit includes a first switch circuit, and the low-voltage startup path unit includes a second switch circuit;

[0041] Wherein, the first end of the first current limiting resistor and the first switch access end of the second switch circuit are connected to the input voltage, and the second end of the first current limiting resistor is connected to the first switch access end of the first switch circuit;

[0042] The second switch access terminal of the first switch circuit and the second switch access terminal of the second switch circuit are connected to serve as an output terminal of the output voltage;

[0043] The switch control terminal of the first switch circuit inputs the first clamping protection voltage;

[0044] The second clamping protection voltage is input to the switch control terminal of the second switch circuit.

[0045] In some examples, the switching circuit may be an electronic switch, such as a transistor that is used to form a high-power, high-speed electronic switch.

[0046] A path is formed by controlling the switch circuit under the clamping protection voltage, so that the switch circuit is used to establish a corresponding output voltage Vout for the input voltage Vin.

[0047] In some embodiments, a field effect transistor may be selected as the electronic switch.

[0048] like Figure 3 As shown, the first switch circuit includes a first transistor NM1, and the second switch circuit includes a second transistor NM2;

[0049] The gate of the first transistor NM1, the first switch access terminal of the first transistor NM1 and the second terminal of the first current limiting resistor R1 are respectively connected to the first clamping protection voltage V1;

[0050] The gate of the second transistor NM2 is connected to the second clamping protection voltage V2, and the first switch access terminal of the second transistor NM2 is connected to the input voltage Vin;

[0051] The second switch access terminal of the first transistor NM1 and the second switch access terminal of the second transistor NM2 are connected to serve as an output terminal of the output voltage Vout.

[0052] In implementation, the transistors may be selected from corresponding MOS transistors according to the circuit design, that is, the first transistor and the second transistor may be of the same or different types. Preferably, the first transistor NM1 and the second transistor NM2 are both NMOS transistors.

[0053] In some embodiments, as Figure 3 As shown, the first transistor NM1 includes a first NMOS tube, and the second transistor includes a second NMOS tube. At this time, the body well end of the first NMOS tube is connected to a first reference potential (a reference potential lower than the VOUT potential as shown in the figure), wherein the first reference potential is a potential lower than the output voltage.

[0054] When the input voltage Vin of the startup circuit is low (e.g., approximately 3V), the current flowing through R2 is very small due to the voltage divider relationship between the first current-limiting resistor R1 and the second current-limiting resistor R2, and the two current-limiting resistors are usually in the megohm range. Therefore, the voltage difference across R2 is very small, that is, the difference between the first clamping protection voltage V1 and the second clamping protection voltage V2 is very small. Since the sources of NMOS transistors NM1 and NM2 are connected to the same potential, that is, the output voltage "Vout", and the voltage difference between the gates of NM1 and NM2 is very small, the gate-source voltage difference between the two is Vgs1≈Vgs2. However, because the body well of NM1 is connected to a "reference voltage lower than Vout potential", the threshold voltage of NM2 is lower than that of NM1 due to the body effect of the MOSFET. Therefore, under low input voltage conditions, NM2 is turned on, and the current I CH2 Flows from the low-voltage startup path unit 300, and the path is Vin->NM2, so that a stable output voltage Vout is established for the input voltage Vin through the low-voltage startup path unit 300 (ie, NM2);

[0055] When the input voltage Vin of the startup circuit is high (for example, about 80V), the current flowing through R2 is much larger than that in the low input voltage condition in the above example, so there is a large voltage difference across R2, that is, the difference between the first clamping protection voltage V1 and the second clamping protection voltage V2 is large. Therefore, the gate voltage of NM2 is smaller than the gate voltage of NM1. Since the sources of NM1 and NM2 are connected to the same potential "Vout", it can be obtained that Vgs2<Vgs1 at this time. At this time, the threshold change caused by the body effect is smaller than the gate-source voltage difference between the two, that is, the voltage difference across R2, so under high input voltage conditions, NM1 is turned on and the current I CH1 The voltage flows from the high-voltage startup path unit 200 , and the path is Vin->NM1 , thereby establishing a stable output voltage Vout.

[0056] In some embodiments, the voltage clamping branch may be a voltage-stabilized voltage clamping circuit structure composed of a current-limiting resistor and a voltage stabilizer.

[0057] like Figure 3 As shown, the auxiliary protection unit 100 includes a voltage clamping branch, and the voltage clamping branch includes a second current limiting resistor R2 and a voltage regulator Z1;

[0058] Wherein, the first end of the second current limiting resistor R2 is connected to the second end of the first current limiting resistor R1 and serves as the output end of the first clamping protection voltage V1;

[0059] The second end of the second current limiting resistor R2 is connected to the voltage stabilization output end of the voltage stabilizer Z1 and serves as the output end of the second clamping protection voltage V2.

[0060] In practice, the voltage regulator Z1 may preferably be a voltage regulator diode, and more preferably, the voltage regulator value of the voltage regulator diode is 5V.

[0061] It should be noted that the voltage stabilizer Z1 can be selected according to application requirements, and a voltage stabilizing diode is preferably used here for schematic illustration.

[0062] In some embodiments, the resistance value of the first current limiting resistor R1 is greater than the resistance value of the second current limiting resistor R2, which not only reduces the overall circuit power consumption, but also provides more branch current for the high-voltage startup path unit, achieving better energy recovery and utilization, and lower overall power consumption.

[0063] In some embodiments, when carrying a high input voltage (e.g., 80V or higher) and a low output current, a small current will flow through the high-voltage branch to the load, while the second current-limiting resistor R2 will carry a large current, resulting in a large voltage difference across the resistor. This voltage difference may exceed the normal control voltage of the high-voltage startup path unit 200, such as the gate breakdown threshold of NM1, thereby causing device burnout. Therefore, a protection circuit can be introduced into the auxiliary protection unit 100.

[0064] In practice, a corresponding protection switch circuit may be added to the auxiliary protection unit 100 to limit the difference between the first clamping protection voltage V1 and the second clamping protection voltage V2 when the protection switch circuit is operating.

[0065] like Figure 3 As shown, the voltage clamping branch further includes a third transistor PM1. Preferably, the third transistor includes a PMOS transistor.

[0066] The gate of the third transistor PM1 is connected to the second clamping protection voltage V2, the first switch access terminal (such as the source) of the third transistor PM1 is connected to the second clamping protection voltage V2, and the second switch access terminal of the third transistor PM1 is grounded.

[0067] By using the switch tube PM1 to discharge and shunt the current, the current flowing through R2 is reduced, the gate of NM1 is prevented from being broken down, and the circuit operates stably.

[0068] Based on the same inventive concept, this specification also provides a power manager with a wide input voltage range. Specifically, the startup circuit included in this power manager with a wide input voltage range is the startup circuit described in any of the aforementioned embodiments. This enables the power manager to meet low power consumption and a wide input voltage range while further reducing the chip layout area, facilitating its application in various power supply applications.

[0069] It should be noted that the embodiments of this specification only provide an illustrative description of the startup circuit in the power manager, and those skilled in the art should be able to obtain relevant information about other circuits from the power manager in the prior art, so the other circuits in the power manager are not described in detail.

[0070] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on the differences from other embodiments.

[0071] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present application should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A startup circuit with a wide input voltage range, characterized in that: include: Auxiliary protection unit, first current limiting resistor, high voltage starting path unit and low voltage starting path unit; The first end of the first current limiting resistor is connected to the input voltage, and the second end of the first current limiting resistor is connected to the auxiliary protection unit and the high-voltage startup path unit respectively, so as to provide the auxiliary protection unit and the high-voltage startup path unit with the working current required for operation; The auxiliary protection unit is used to form a first clamping protection voltage and a second clamping protection voltage under the action of the working current, and output the first clamping protection voltage to the high-voltage startup path unit, and output the second clamping protection voltage to the low-voltage startup path unit; When the input voltage is higher than a first threshold, the difference between the first clamping protection voltage and the second clamping protection voltage formed by the auxiliary protection unit is greater than a second threshold, so that the high-voltage startup path unit establishes an output voltage corresponding to the input voltage under the control of the first clamping protection voltage; and when the input voltage is not higher than the first threshold, the difference between the first clamping protection voltage and the second clamping protection voltage formed by the auxiliary protection unit is not greater than the second threshold, so that the low-voltage startup path unit establishes the output voltage corresponding to the input voltage under the control of the second clamping protection voltage; The high-voltage startup path unit includes a first switch circuit, and the low-voltage startup path unit includes a second switch circuit; Wherein, the first end of the first current limiting resistor and the first switch access end of the second switch circuit are connected to the input voltage, and the second end of the first current limiting resistor is connected to the first switch access end of the first switch circuit; The second switch access terminal of the first switch circuit and the second switch access terminal of the second switch circuit are connected to serve as an output terminal of the output voltage; The switch control terminal of the first switch circuit inputs the first clamping protection voltage; The switch control terminal of the second switch circuit inputs the second clamping protection voltage; The auxiliary protection unit includes a voltage clamping branch, and the voltage clamping branch includes a second current limiting resistor and a voltage stabilizer; Wherein, the first end of the second current limiting resistor is connected to the second end of the first current limiting resistor and serves as the output end of the first clamping protection voltage; The second end of the second current limiting resistor is connected to the voltage stabilization output end of the voltage stabilizer and serves as the output end of the second clamping protection voltage.

2. The startup circuit with a wide input voltage range according to claim 1, characterized in that: The first switch circuit includes a first transistor, and the second switch circuit includes a second transistor; The gate of the first transistor, the first switch access terminal of the first transistor and the second terminal of the first current limiting resistor are respectively connected to the first clamping protection voltage; The gate of the second transistor is connected to the second clamping protection voltage, and the first switch access terminal of the second transistor is connected to the input voltage; The second switch access terminal of the first transistor and the second switch access terminal of the second transistor are connected to serve as an output terminal of the output voltage.

3. The startup circuit with a wide input voltage range according to claim 2, characterized in that: The first transistor includes a first NMOS transistor, the second transistor includes a second NMOS transistor, a body well terminal of the first NMOS transistor is connected to a first reference potential, wherein the first reference potential is a potential lower than the output voltage.

4. The startup circuit with a wide input voltage range according to claim 1, wherein: The voltage regulator includes a voltage regulator diode; and / or the resistance value of the first current limiting resistor is greater than the resistance value of the second current limiting resistor.

5. The startup circuit with a wide input voltage range according to claim 4, characterized in that: The voltage stabilization value of the voltage stabilizing diode is 5V.

6. The startup circuit with a wide input voltage range according to claim 1, wherein: The clamping branch further includes a third transistor, a gate of the third transistor is connected to the second clamping protection voltage, a first switch access terminal of the third transistor is connected to the second clamping protection voltage, and a second switch access terminal of the third transistor is grounded.

7. The startup circuit with a wide input voltage range according to claim 6, characterized in that: The third transistor includes a PMOS transistor.

8. A power manager with a wide input voltage range, comprising a startup circuit, characterized in that: The startup circuit is a startup circuit with a wide input voltage range as claimed in any one of claims 1 to 7.

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