Automatic hot start enhanced low dropout regulator circuit

Abstract

The utility model relates to the technical field of voltage regulation, and discloses a low dropout linear regulator circuit capable of enhancing automatic hot start. The circuit comprises a preceding stage voltage stabilizing circuit which is connected to a power supply interface, is internally provided with a voltage reduction branch circuit and a direct connection branch circuit, and is connected with and controls either-or switching of the voltage reduction branch circuit and the direct connection branch circuit through a control chip; the low-dropout voltage stabilizer is connected to the pre-stage voltage stabilizing circuit, and the input end and the output end of the low-dropout voltage stabilizer are respectively connected to the ADC port of the control chip in a branched manner; the DC-DC voltage regulating circuit is connected to the low-dropout voltage stabilizer, a voltage regulating branch and a straight-through branch are arranged in the DC-DC voltage regulating circuit, a control chip is used for connecting and controlling either-or switching of the voltage regulating branch and the straight-through branch, a variable resistor is arranged in the voltage regulating branch, and an output end branch is connected to an ADC (Analog to Digital Converter) port of the control chip; and a control chip. According to the LDO voltage reduction and stabilization circuit, selectable voltage reduction and stabilization control over LDO input voltage can be achieved through the circuit as simple as possible, and due to the fact that the whole circuit is simple and easy to achieve, the space requirement is extremely small, and the LDO voltage reduction and stabilization circuit can be well applied to the space limited situation.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of voltage regulation, particularly relates to the system of regulating electric variable or magnetic variable. BACKGROUND

[0002] Low-Dropout Voltage Regulator (LDO) is a kind of DC linear voltage regulator with input voltage greater than output voltage, it has the advantages of input-output response fast, low noise, etc., can be applied to the power supply of DDR (Double Data Rate), DDR2 (Double Data Rate 2) and other memories, DDR, DDR2 and other memories need power supply with strong load capacity, high output precision, good transient performance and can pour / large current.

[0003] In practice, the main problem of using LDO is that the input voltage needs to be relatively stable, generally, for the non-steady state of low input voltage, the reactive compensation realized by capacitor is sufficient to meet the vast majority of demand, but for the non-steady state of high input voltage, it is more troublesome, on the one hand, if the voltage is directly added to the voltage reduction circuit, when the voltage is low in the normal range, the input voltage of LDO is continuously low due to the additional voltage reduction circuit, and the reactive compensation of capacitor is difficult to last, on the other hand, when LDO is currently applied, it is often in the condition of limited space, and it is also difficult to add complex additional voltage stabilizing circuit.

[0004] Therefore, one solution in the prior art is to integrate the voltage stabilizing circuit in the overall LDO circuit, such as the "Low-Dropout Voltage Regulator Start Circuit and Low-Dropout Voltage Regulator" disclosed in the Chinese patent with application number CN202410692418.7.

[0005] The inventor found that at least the following problems exist in the prior art: the existing LDO is generally a complete independent element, and its internal circuit can only be selected for selection, that is, the internal circuit of the LDO can only be selected and cannot be changed; without changing the internal circuit of the LDO, the external circuit is often too complex to be applied to the space-limited condition. UTILITY MODEL CONTENT

[0006] The utility model aims at providing a kind of low voltage difference linear voltage regulator circuit of automatic thermal start enhancement, so that the selectivity voltage reduction and voltage stabilization control of LDO input voltage can be realized with as simple as possible circuit, and since the overall circuit is simple and easy to realize, the space requirement is extremely small, and it can be well applied to the space-limited condition.

[0007] The utility model provides a kind of low voltage difference linear voltage regulator circuit of automatic thermal start enhancement, including:

[0008] The front stage voltage stabilizing circuit is connected to the power interface, and has a voltage reduction branch and a direct connection branch, and a two-way switch controlled by the control chip is connected to control the voltage reduction branch and the direct connection branch.

[0009] The low voltage difference voltage regulator is connected to the front stage voltage stabilizing circuit, and the input end and the output end are respectively branched to the ADC port of the control chip.

[0010] The DC-DC voltage regulating circuit is connected to the low voltage difference voltage regulator, and has a voltage regulating branch and a straight-through branch, and a two-way switch controlled by the control chip is connected to control the voltage regulating branch and the straight-through branch, and the voltage regulating branch has a variable resistor, and the output end is branched to the ADC port of the control chip.

[0011] The control chip is connected to control the switch of the voltage reduction branch and the direct connection branch in the front stage voltage stabilizing circuit through a GPIO port, and is connected to control the switch of the voltage reduction branch and the straight-through branch in the DC-DC voltage regulating circuit through another GPIO port, and is connected to control the variable resistor in the DC-DC voltage regulating circuit through a PWM port.

[0012] In the front stage voltage stabilizing circuit, the voltage reduction branch has a first optocoupler U1 in series, the direct connection branch has a second optocoupler U2 in series, and the first optocoupler U1 and the second optocoupler U2 are reversely connected and controlled by a GPIO port of the control chip.

[0013] In the DC-DC voltage regulating circuit, the voltage regulating branch has a third optocoupler U3 in series, the straight-through branch has a fifth optocoupler U5 in series, and the third optocoupler U3 and the fifth optocoupler U5 are reversely connected and controlled by a GPIO port of the control chip.

[0014] The reverse connection control is that the GPIO port directly connects the optocoupler on one branch to make the optocoupler circuit connected when the high level, and the optocoupler is short-circuited by a transistor in parallel on the other branch to make the optocoupler circuit connected when the low level.

[0015] In the voltage regulating circuit of the DC-DC voltage regulating circuit, a fourth optocoupler U4 is connected in parallel to the variable resistor, and the fourth optocoupler is connected and controlled by a GPIO port of the control chip.

[0016] The voltage reduction circuit in the front stage voltage stabilizing circuit is a Zener voltage stabilizing circuit.

[0017] In the Zener voltage stabilizing circuit, a Zener diode with Zener breakdown is connected in a reverse bias mode.

[0018] The power supply Vcc of the control chip is connected from the position between the low voltage difference voltage regulator and the DC-DC voltage regulating circuit.

[0019] The power supply of the control chip is also connected with a battery, and the power supply Vcc access point is connected with the battery through a double PMOS tube power supply switching circuit and then connected with the power supply port of the control chip.

[0020] Compared with the prior art, the LDO input voltage selectivity voltage reduction and stabilization control can be realized by the simplest circuit, the overall circuit is simple and easy to realize, the space requirement is extremely small, and the circuit can be well applied to the space limited condition.

[0021] The above description is only a summary of the technical scheme of the utility model, in order to more clearly understand the technical means of the utility model, the contents of the specification can be implemented, and in order to make the above and other purposes, characteristics and advantages of the utility model more obvious and easy to understand, the specific embodiment of the utility model is as follows. BRIEF DESCRIPTION OF DRAWINGS

[0022] One or more embodiments are illustrated by way of example in the drawings that are for illustrative purposes only, and these illustrative examples do not constitute a limitation on the embodiments, elements with the same reference numerals in the drawings represent similar elements, unless otherwise specified, the drawings do not constitute a proportional limit.

[0023] Figure 1 is a connection diagram of at least one embodiment of the utility model;

[0024] Figure 2 is Figure 1 a connection diagram of the front-stage voltage stabilization circuit;

[0025] Figure 3 is Figure 1 a connection diagram of the low-voltage difference voltage stabilizer;

[0026] Figure 4 is Figure 1 a connection diagram of the DC-DC voltage regulation circuit;

[0027] Figure 5 is Figure 1 a connection diagram of the control chip. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical scheme and advantages of the utility model clearer, the various embodiments of the utility model will be described in detail below in combination with the drawings. However, those skilled in the art can understand that, in the various embodiments of the utility model, many technical details are proposed in order to enable the readers to better understand the present application. However, even if there are no such technical details and various changes and modifications based on the following embodiments, the technical scheme claimed in the present application can also be realized. The division of the following embodiments is for the convenience of description, and should not constitute any limitation on the specific implementation of the utility model, and the various embodiments can be combined and quoted with each other under the premise of no contradiction.

[0029] The first embodiment of the utility model relates to an automatic hot start enhanced low dropout linear regulator circuit as shown in the figure, comprising: Figures 1 to 5

[0030] The front stage voltage stabilizing circuit is connected to the power interface, has a voltage reduction branch and a direct connection branch, and a two-way switch for controlling the voltage reduction branch and the direct connection branch is connected to the control chip;

[0031] The low dropout voltage regulator is connected to the front stage voltage stabilizing circuit, and the input end and the output end are respectively branched to the ADC port of the control chip;

[0032] The DC-DC voltage regulating circuit is connected to the low dropout voltage regulator, has a voltage regulating branch and a straight-through branch, and a two-way switch for controlling the voltage regulating branch and the straight-through branch is connected to the control chip, the voltage regulating branch has a variable resistor, and the output end is branched to the ADC port of the control chip;

[0033] The control chip is connected to the two-way switch for controlling the voltage reduction branch and the direct connection branch in the front stage voltage stabilizing circuit through a GPIO port, is connected to the two-way switch for controlling the voltage reduction branch and the straight-through branch in the DC-DC voltage regulating circuit through another GPIO port, and is connected to the variable resistor in the DC-DC voltage regulating circuit through a PWM port.

[0034] ​Thus, in the default state, the direct connection branch in the pre-stage voltage stabilization circuit is powered on, and the control chip can obtain the input voltage of the LDO (i.e. low dropout regulator, i.e. low dropout linear regulator, same below) from the input end of the LDO to determine whether the buck branch in the pre-stage voltage stabilization circuit needs to be powered on; at the same time, the control chip can obtain the output voltage of the LDO from the output end of the LDO to determine whether the LDO is working normally, and also facilitate the determination of the voltage regulation control of the DC-DC voltage regulation circuit. In order to ensure a wider range of applications, in actual use, the LDO is generally selected to be a model with an output voltage higher than the voltage demand of the application circuit, and then the DC-DC voltage regulation circuit is further used for voltage reduction, so as to realize a wider range of applications, and the variable resistor in the DC-DC voltage regulation circuit is adjusted to realize precise voltage regulation in a wider range, for example, the LDO can be fixedly selected to be a model with an output voltage of 18V, at this time, for an application with a voltage demand of 12V, the buck can be realized by controlling the variable resistor, and if the continuous low voltage condition occurs, the output voltage of the LDO will be 16V, and only the corresponding control of the variable resistor is needed to ensure that the final output voltage is still 12V.

[0035] It is worth mentioning that each module involved in the embodiment is a logical module, and in actual application, one logical unit can be one physical unit, or a part of one physical unit, or realized by combination of multiple physical units. In addition, in order to highlight the innovative part of the utility model, units not closely related to solving the technical problems proposed in the utility model are not introduced in the embodiment, but this does not mean that other units do not exist in the embodiment.

[0036] The second embodiment of the utility model is basically the same as the first embodiment, and the main difference is that in the pre-stage voltage stabilization circuit, the buck branch is connected in series with the first optocoupler U1, and the direct connection branch is connected in series with the second optocoupler U2, and the first optocoupler U1 and the second optocoupler U2 are reversely connected and controlled by one GPIO port of the control chip.

[0037] Further, in the DC-DC voltage regulation circuit, the voltage regulation branch is connected in series with the third optocoupler U3, and the direct connection branch is connected in series with the fifth optocoupler U5, and the third optocoupler U3 and the fifth optocoupler U5 are reversely connected and controlled by one GPIO port of the control chip.

[0038] Still further, the reverse connection control is that the GPIO port directly connects the optocoupler on one branch to make the optocoupler circuit connected when the high level, and the optocoupler on the other branch is connected in parallel through the triode to make the optocoupler circuit connected when the low level.

[0039] Preferably, the fourth optocoupler U4 is connected in parallel to the variable resistor in the voltage regulation circuit of the DC-DC voltage regulation circuit, and the fourth optocoupler U4 is connected and controlled by one GPIO port of the control chip. The main function of the fourth optocoupler U4 is temporary protective disconnection of power supply.

[0040] The third embodiment of this utility model is largely the same as the first embodiment, except that the step-down circuit in the front-end voltage regulator circuit is a Zener voltage regulator circuit.

[0041] Furthermore, such as Figure 3 In the Zener regulator circuit shown, a Zener diode with Zener breakdown is connected in reverse bias. When the applied reverse bias voltage approaches the Zener voltage, the electric field strength in the depletion region is sufficient to pull electrons out of their valence band. Valence electrons, gaining sufficient energy from the strong electric field in the depletion region, detach from their parent atoms. In the Zener breakdown region, a small increase in voltage leads to a rapid increase in current. Therefore, the Zener diode selection must correspond to the upper limit of the LDO's input voltage, so that the voltage exceeding the upper limit of the LDO's input voltage is divided by Zener breakdown.

[0042] Furthermore, the power supply Vcc for the control chip is connected between the low-dropout regulator and the DC-DC voltage regulator circuit. Therefore, the LDO's output voltage is also the control chip's input voltage. Based on the control chip obtaining the LDO's output voltage from its output terminal, it can help determine whether the control chip needs to switch its operating voltage (this is mainly effective for some control chips with this function).

[0043] Furthermore, such as Figure 5 As shown, the control chip is also connected to a battery. The power supply Vcc input point and the battery are connected to the control chip's power supply port via a dual PMOS transistor power switching circuit. This allows for automatic switching between battery power and LDO output voltage (i.e., power supply Vcc). Furthermore, comparing the LDO output voltage with the battery voltage helps determine the battery level, thus significantly saving circuit wiring space.

[0044] Since the second embodiment corresponds to this embodiment, this embodiment can be implemented in conjunction with the second embodiment. The relevant technical details mentioned in the second embodiment remain valid in this embodiment, and the technical effects achievable in the second embodiment can also be realized in this embodiment. To reduce repetition, they will not be repeated here. Correspondingly, the relevant technical details mentioned in this embodiment can also be applied to the second embodiment.

[0045] Those skilled in the art will understand that the above embodiments are specific examples of implementing the present invention, and in practical applications, various changes can be made to them in form and detail without departing from the spirit and scope of the present invention.

Claims

1. An auto-heat-up enhanced low-dropout linear regulator circuit, comprising: include: The pre-stage voltage regulator circuit is connected to the power interface and contains a step-down branch and a direct-connect branch. The control chip controls the switching between the step-down branch and the direct-connect branch. The low dropout regulator is connected to the pre-stage voltage regulator circuit, with its input and output terminals respectively branched to the ADC port of the control chip. The DC-DC voltage regulation circuit is connected to the low dropout voltage regulator. It contains a voltage regulation branch and a direct-through branch. The control chip controls the switching between the voltage regulation branch and the direct-through branch. The voltage regulation branch contains a variable resistor, and the output is branched to the ADC port of the control chip. The control chip controls the switching between the step-down branch and the direct-drive branch in the pre-stage voltage regulator circuit through one GPIO port, controls the switching between the step-down branch and the direct-drive branch in the DC-DC voltage regulator circuit through another GPIO port, and controls the variable resistor in the DC-DC voltage regulator circuit through another PWM port.

2. The automatic thermal enable enhanced low-dropout linear regulator circuit of claim 1, wherein, In the pre-stage voltage regulator circuit, the step-down branch is connected in series with the first optocoupler U1, and the direct-connect branch is connected in series with the second optocoupler U2. The first optocoupler U1 and the second optocoupler U2 are controlled by a reverse connection of one GPIO port of the control chip.

3. The auto-heat-up enhanced low-dropout linear regulator circuit of claim 1, wherein, In the DC-DC voltage regulation circuit, the voltage regulation branch is connected in series with the third optocoupler U3, and the direct-through branch is connected in series with the fifth optocoupler U5. The third optocoupler U3 and the fifth optocoupler U5 are controlled by a reverse connection of one GPIO port of the control chip.

4. The auto-heat-up enhanced low-dropout linear regulator circuit of claim 2 or 3, wherein, The reverse connection control is as follows: on one branch, the GPIO port is directly connected to the optocoupler to make the optocoupler circuit connected when the level is high; on the other branch, the optocoupler is shorted in parallel through a transistor to make the optocoupler circuit connected when the level is low.

5. The auto-heat-up enhanced low-dropout linear regulator circuit of claim 1, wherein, The DC-DC voltage regulation circuit contains a fourth optocoupler U4 connected in parallel with a variable resistor. The fourth optocoupler is controlled by the control chip through a GPIO port.

6. The automatic heat-up enhancement low-dropout linear regulator circuit of claim 1, wherein, The step-down circuit in the pre-stage voltage regulator circuit is a Zener voltage regulator circuit.

7. The automatic startup enhancement low-dropout linear regulator circuit of claim 6, wherein, In the Zener voltage regulator circuit, Zener diodes with Zener breakdown are connected in a reverse bias manner.

8. The automatic heat-up enhancement low-dropout linear regulator circuit of claim 1, wherein, The power supply Vcc of the control chip is connected from the location between the low-dropout regulator and the DC-DC voltage regulation circuit.

9. The self-heat-up enhanced low-dropout linear regulator circuit of claim 1, wherein, The control chip is also connected to a battery for power supply. The power supply Vcc input point and the battery are connected to the power supply port of the control chip through a dual PMOS power switching circuit.

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