Power supply circuit

Abstract

A power supply circuit includes a first voltage regulator and a second voltage regulator. The first voltage regulator is configured to generate a first output signal in response to an input signal. A voltage value of the first output signal is decreased in response to the input signal and a first voltage threshold during a power-off phase. The second voltage regulator is configured to be enabled in response to the first output signal to generate a second output signal in response to the input signal. A voltage value of the second output signal is decreased in response to the input signal and a second voltage threshold during the power-off phase. The second voltage threshold is greater than the first threshold.

Description

Technical Field

[0001] The embodiments described in this disclosure relate to a power supply technology, and more particularly to a power supply circuit that utilizes a voltage regulator to control timing. Background Art

[0002] With the advancement of technology, power supply technology has been applied to various electronic devices. Some related technologies use resistors and capacitors to control power sequencing. However, resistors and capacitors are highly sensitive to environmental changes (such as temperature). Furthermore, with the evolution of manufacturing processes, new control methods are needed to effectively control power sequencing. Summary of the Invention

[0003] Some embodiments of the present disclosure relate to a power supply circuit. The power supply circuit includes a first voltage regulator and a second voltage regulator. The first voltage regulator is configured to generate a first output signal based on an input signal. The voltage of the first output signal decreases during a power-off phase based on the input signal and a first voltage threshold. The second voltage regulator is configured to be enabled based on the first output signal to generate a second output signal based on the input signal. The voltage of the second output signal decreases during a power-off phase based on the input signal and a second voltage threshold. The second voltage threshold is greater than the first threshold.

[0004] In summary, the present disclosure utilizes a voltage regulator to control power supply timing. This prevents power supply timing changes due to environmental variations (e.g., temperature). Furthermore, the present disclosure effectively controls the voltage rise time of a relatively low-voltage output signal to occur earlier than that of a relatively high-voltage output signal, and the voltage fall time of a relatively high-voltage output signal to occur earlier than that of a relatively low-voltage output signal. This diverse voltage supply mode can adapt to new process technologies. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] In order to make the above and other objects, features, advantages and embodiments of the present disclosure more apparent and understandable, the accompanying drawings are described as follows:

[0006] Figure 1 is a schematic diagram of a power supply circuit according to some embodiments of the present disclosure;

[0007] Figure 2 According to some embodiments of the present disclosure Figure 1 A timing diagram of multiple signals of a power supply circuit;

[0008] Figure 3 is a power-on flowchart of a power supply circuit according to some embodiments of the present disclosure;

[0009] Figure 4 is a power-off flowchart of a power supply circuit according to some embodiments of the present disclosure; and

[0010] Figure 5 4 is a circuit diagram of a comparison circuit and a discharge circuit of a voltage regulator according to some embodiments of the present disclosure. DETAILED DESCRIPTION

[0011] In this document, unless otherwise specified, "a," "an," and "the" may refer to a single or a plurality of items. It will be further understood that "comprising," "including," "having," and similar words used herein specify the features, regions, integers, steps, operations, elements, and / or components described herein, but do not exclude the described or additional features, regions, integers, steps, operations, elements, components, and / or combinations thereof.

[0012] As used herein, the term “coupled” may also refer to “electrically coupled,” and the term “connected” may also refer to “electrically connected.” “Coupled” and “connected” may also refer to two or more elements cooperating or interacting with each other.

[0013] The following drawings illustrate various embodiments of the present invention. It should be understood that these implementation details are not intended to limit the present invention. In other words, these implementation details are not essential for some embodiments of the present invention. Furthermore, to simplify the drawings, some commonly used structures and components are depicted in simplified schematic form.

[0014] refer to Figure 1 . Figure 1 FIG2 is a schematic diagram of a power supply circuit 100 according to some embodiments of the present disclosure. In some embodiments, the power supply circuit 100 is disposed in a mobile phone, a laptop computer, or other various electronic devices.

[0015] The power supply circuit 100 is configured to provide output signals VOUT1 and VOUT2 based on an input signal VIN to power other circuits in the aforementioned electronic devices. In some embodiments, the input signal VIN can be generated by transformer-transforming a raw supply voltage. The raw supply voltage can have a maximum voltage of 12 volts, while the input signal VIN can have a maximum voltage of 5 volts. In some embodiments, the maximum voltage of the output signal VOUT1 is less than the maximum voltage of the output signal VOUT2. For example, the maximum voltage of the output signal VOUT1 can be 1.8 volts, while the maximum voltage of the output signal VOUT2 can be 3.3 volts.

[0016] However, the present disclosure is not limited to the above maximum voltage values. Other applicable maximum voltage values ​​are within the scope of the present disclosure.

[0017] by Figure 1For example, the power supply circuit 100 includes a voltage regulator 120 and a voltage regulator 140 .

[0018] The voltage regulator 120 includes an input terminal P1 and an output terminal P2. The input terminal P1 is used to receive an input signal VIN. The voltage regulator 120 is used to generate an output signal VOUT1 at the output terminal P2 according to the input signal VIN.

[0019] The voltage regulator 140 includes an enable terminal PEN, an input terminal P3, an output terminal P4, a discharge circuit 142, and other internal circuitry (not shown). The voltage regulator 140 receives an output signal VOUT1 from the output terminal P2 of the voltage regulator 120 via the enable terminal PEN. The output signal VOUT1 enables the voltage regulator 140. The input terminal P3 receives an input signal VIN. When the voltage regulator 140 is enabled by the output signal VOUT1, the other internal circuitry of the voltage regulator 140 generates an output signal VOUT2 at the output terminal P4 based on the input signal VIN. The discharge circuit 142 is coupled between the output terminal P4 and the ground terminal GND.

[0020] refer to Figure 2 . Figure 2 According to some embodiments of the present disclosure Figure 1 1 is a timing diagram of multiple signals of the power supply circuit 100.

[0021] Figure 2 The timing diagram includes two consecutive time intervals. From left to right (i.e., in the direction of time flow), they are the power-on phase P_ON and the power-off phase P_OFF. Time points T1 and T2 fall within the power-on phase P_ON, with T1 occurring earlier than T2. ​​Time points T3 and T4 fall within the power-off phase P_OFF, with T3 occurring earlier than T4.

[0022] Figure 3 FIG. 1 is a power-on flowchart of the power supply circuit 100 according to some embodiments of the present disclosure. Figure 1 as well as Figure 2 right Figure 3 Provide explanation.

[0023] In operation S302, an adapter is inserted into the electronic device. For example, one end of the adapter can be coupled to the input terminal P1 of the power supply circuit 100 in the electronic device, while the other end of the adapter can be used to receive AC power. The adapter supplies power to the power supply circuit 100 based on the AC power.

[0024] In operation S304, the voltage value of the input signal VIN starts to rise. Figure 2For example, when the adapter is plugged into the electronic device, the voltage of the input signal VIN begins to rise, entering the power-on phase P_ON. When the voltage of the input signal VIN reaches the maximum voltage of the input signal VIN (e.g., 5V), the input signal VIN enters a steady state (as indicated by the horizontal line in the figure).

[0025] In operation S306, the voltage regulator 120 starts to operate. Figure 2 For example, at time T1, the voltage of the input signal VIN rises to approximately the voltage threshold VTH1 (e.g., 2.5 volts, but not limited thereto) corresponding to the voltage regulator 120. At this point, the output signal VOUT1 of the voltage regulator 120 begins charging based on the input signal VIN. Specifically, when the voltage of the input signal VIN is equal to or greater than the voltage threshold VTH1 during the power-on phase P_ON, the voltage regulator 120 is enabled, causing the voltage of the output signal VOUT1 to rise. When the voltage of the output signal VOUT1 reaches the maximum voltage of the voltage regulator 120 (e.g., 1.8 volts), the output signal VOUT1 enters a steady state.

[0026] In operation S308, the voltage regulator 140 starts to operate. Figure 2 For example, at time T2, the voltage value of the output signal VOUT1 input to the enable terminal PEN of the voltage regulator 140 rises to approximately the voltage threshold VTH3 corresponding to the voltage regulator 140 (e.g., 1.08 volts, but not limited thereto). At this point, the voltage regulator 140 is enabled and the output signal VOUT2 begins charging based on the input signal VIN. That is, when the voltage value of the output signal VOUT1 is equal to or greater than the voltage threshold VTH3 during the power-on phase P_ON, the voltage regulator 140 is enabled, causing the voltage value of the output signal VOUT2 to rise. When the voltage value of the output signal VOUT2 rises to the maximum voltage value of the voltage regulator 140 (e.g., 3.3 volts), the output signal VOUT2 enters a steady state. In this embodiment, the voltage threshold VTH3 is lower than the voltage threshold VTH1.

[0027] In operation S310 , the electronic device is started up. The output signal VOUT1 and the output signal VOUT2 in a steady state can power other circuits in the electronic device, thereby starting up the electronic device and starting normal operation.

[0028] In some related art electronic devices, a circuit powered by a relatively high voltage starts operating earlier than a circuit powered by a relatively low voltage.

[0029] As previously mentioned, in some embodiments of the present disclosure, the maximum voltage value of output signal VOUT1 (e.g., 1.8 volts) is lower than the maximum voltage value of output signal VOUT2 (e.g., 3.3 volts). Therefore, compared to the aforementioned related art, in these embodiments, the component supplying a relatively low voltage (regulator 120) in power supply circuit 100 begins operating first, supplying the low-voltage output signal VOUT1 to the corresponding circuit and enabling the component supplying a high voltage (regulator 140), allowing the circuit powered by the relatively high voltage to begin operating later. This voltage supply mode is adaptable to new process technologies (e.g., 12nm or other newer processes).

[0030] Figure 4 FIG. 1 is a flowchart of power-off of the power supply circuit 100 according to some embodiments of the present disclosure. Figure 1 as well as Figure 2 right Figure 4 Provide explanation.

[0031] In operation S402 , the adapter is unplugged from the electronic device.

[0032] In operation S404, the voltage value of the input signal VIN begins to decrease. Figure 2 For example, when the adapter is unplugged from the electronic device, the voltage of the input signal VIN begins to drop, ie, the device enters the power-off phase P_OFF.

[0033] In operation S406, the voltage regulator 140 ends its operation. Figure 2 For example, at time T3, the voltage of the input signal VIN drops to a voltage threshold VTH2 (e.g., 4.2 volts, but not limited thereto) corresponding to the voltage regulator 140. In some embodiments, the voltage threshold VTH2 is the undervoltage lockout (UVL) voltage of the voltage regulator 140. At this point, the discharge circuit 142 of the voltage regulator 140 turns on, causing the output signal VOUT2 to begin rapidly discharging. That is, when the voltage of the input signal VIN is equal to or less than the voltage threshold VTH2 during the power-off phase P_OFF, the discharge circuit 142 of the voltage regulator 140 is controlled to cause the voltage of the output signal VOUT2 to begin rapidly decreasing.

[0034] by Figure 2For example, the power-off phase P_OFF ​​includes a time interval D1 and a time interval D2, with time interval D2 occurring later than time interval D1. During time interval D1, the discharge circuit 142 is conductive, causing the output signal VOUT2 to discharge rapidly. After entering time interval D2 (for example, when the output signal VOUT2 is equal to 1.2 volts, but not limited thereto), the voltage regulator 140 experiences insufficient power supply, slowing the discharge rate of the output signal VOUT2.

[0035] In operation S408, the voltage regulator 120 ends its operation. Figure 2 For example, at time T4, the voltage of the input signal VIN drops to a voltage threshold VTH1 (e.g., 2.5 volts, but not limited thereto) corresponding to the voltage regulator 120. In some embodiments, the voltage threshold VTH1 (e.g., 2.5 volts) serves as the undervoltage lockout voltage of the voltage regulator 120. At this point, the output signal VOUT1 of the voltage regulator 120 begins to discharge. That is, when the voltage of the input signal VIN is equal to or less than the voltage threshold VTH1 during the power-off phase P_OFF, the voltage regulator 120 is controlled to decrease the voltage of the output signal VOUT1.

[0036] Depend on Figure 2 As can be seen from the timing sequence in the present disclosure, in the power-on phase P_ON, the voltage rise time T1 of the low-voltage output signal VOUT1 is earlier than the voltage rise time T2 of the high-voltage output signal VOUT2. In the power-off phase P_OFF, the voltage drop time T3 of the high-voltage output signal VOUT2 is earlier than the voltage drop time T4 of the low-voltage output signal VOUT1.

[0037] In some related technologies, resistors and capacitors are used to control power timing. However, resistors and capacitors are very sensitive to environmental changes (such as temperature changes), which may cause control errors due to environmental changes.

[0038] Compared to the aforementioned related art, the power supply circuit 100 of the present disclosure utilizes voltage regulators 120 and 140 to control the power sequence. Voltage regulators are less susceptible to environmental changes. This prevents the controlled power sequence from changing due to environmental fluctuations. Furthermore, because the voltage threshold VTH2 is greater than the voltage threshold VTH1, during the power-off phase P_OFF, the time point T3 at which the relatively high-voltage output signal VOUT2 begins to decrease is earlier than the time point T4 at which the relatively low-voltage output signal VOUT1 begins to decrease.

[0039] refer to Figure 1 as well as Figure 5 . Figure 5FIG. 1 is a circuit diagram of a discharge circuit 142 and a comparator 144 of a voltage regulator 140 according to some embodiments of the present disclosure.

[0040] by Figure 5 For example, the discharge circuit 142 includes a transistor M1 and a resistor R1. The transistor M1 includes a first terminal, a second terminal, and a control terminal. The first terminal of the transistor M1 is coupled to the ground terminal GND. The second terminal of the transistor M1 is coupled to the first terminal of the resistor R1. The second terminal of the resistor R1 is coupled to the output terminal P4 of the regulator 140 (the output terminal P4 of the regulator 140 is used to output the output signal VOUT2).

[0041] The comparator 144 includes a first input terminal, a second input terminal, and an output terminal. The first input terminal of the comparator 144 is used to receive an input signal VIN. The second input terminal of the comparator 144 is used to receive a voltage threshold VTH2. The comparator 144 is used to compare the voltage value of the input signal VIN with the voltage threshold VTH2 to generate a comparison result signal CR at the output terminal of the comparator 144. The control terminal of the transistor M1 is used to receive the comparison result signal CR to be turned on or off according to the comparison result signal CR. When the input voltage VIN is equal to or less than the voltage threshold VTH2, the transistor M1 will be turned on according to the comparison result signal CR, and the voltage value of the output signal VOUT2 will be quickly pulled down by the transistor M1, as shown in FIG. Figure 2 The voltage of the output signal VOUT2 shown in FIG. 1 is in a decreasing state during the time interval D1 .

[0042] In summary, the present disclosure utilizes a voltage regulator to control power supply timing. This prevents power supply timing changes due to environmental variations (e.g., temperature). Furthermore, the present disclosure effectively controls the voltage rise time of a relatively low-voltage output signal to occur earlier than that of a relatively high-voltage output signal, and the voltage fall time of a relatively high-voltage output signal to occur earlier than that of a relatively low-voltage output signal. This diverse voltage supply mode adapts to new process requirements.

[0043] Various functional elements and modules have been disclosed herein. As will be appreciated by those skilled in the art, a functional module may be implemented by circuitry (whether dedicated circuitry or general-purpose circuitry operating under the control of one or more processors and coded instructions), which generally includes transistors or other circuit elements for controlling the operation of electrical circuits corresponding to the functions and operations described herein. It will be further understood that the specific structure and interconnection of circuit elements may generally be determined by a compiler, such as a register transfer language (RTL) compiler. A register transfer language compiler operates on a script, which is quite similar to assembly language code, and compiles the script into a form used to lay out or fabricate the final circuit.

[0044] Although the present disclosure has been disclosed in the form of an embodiment as described above, it is not intended to limit the present disclosure. Any person skilled in the art may make various changes and improvements without departing from the spirit and scope of the present disclosure. Therefore, the scope of protection of the present disclosure shall be determined by the appended claims.

[0045] Description of reference numerals:

[0046] 100: Power supply circuit

[0047] 120,140: Voltage regulator

[0048] 142: discharge circuit

[0049] 144: Comparator

[0050] VIN: input signal

[0051] VOUT1, VOUT2: output signal

[0052] P1, P3: Input terminal

[0053] P2, P4: output terminal

[0054] PEN: Enable terminal

[0055] P_ON: Power-on phase

[0056] P_OFF: Power-off phase

[0057] T1, T2, T3, T4: time points

[0058] VTH1, VTH2, VTH3: voltage thresholds

[0059] D1, D2: time interval

[0060] M1: transistor

[0061] GND: ground terminal

[0062] R1: resistor

[0063] S302, S304, S306, S308, S310, S402, S404, S406, S408: Operation

Claims

1. A power supply circuit, comprising: a first voltage regulator for generating a first output signal according to an input signal, wherein a voltage value of the first output signal decreases according to the input signal and a first voltage threshold during a power-off phase; as well as A second voltage regulator is configured to be enabled according to the first output signal to start generating a second output signal at its output terminal according to the input signal, wherein the voltage value of the second output signal enters a steady state when it rises to a maximum voltage value of the second voltage regulator, wherein the voltage value of the second output signal decreases according to the input signal and a second voltage threshold during the power-off phase, wherein the second voltage threshold is greater than the first voltage threshold, and a time point at which the voltage of the second output signal starts to decrease is earlier than a time point at which the voltage of the first output signal starts to decrease. 2 . The power supply circuit as claimed in claim 1 , wherein a maximum voltage value of the first output signal is smaller than a maximum voltage value of the second output signal.

3. The power supply circuit of claim 1 , wherein if the voltage value of the input signal is equal to or less than the second voltage threshold during the power-off phase, the second regulator is controlled to decrease the voltage value of the second output signal, wherein the second voltage threshold is an under-voltage lockout voltage of the second regulator.

4. The power supply circuit of claim 3 , wherein if the voltage value of the input signal is equal to or less than the first voltage threshold during the power-off phase, the first regulator is controlled to decrease the voltage value of the first output signal, wherein the first voltage threshold is an under-voltage lockout voltage of the first regulator.

5. The power supply circuit as claimed in claim 3 , wherein the second voltage regulator comprises: The discharge circuit is turned on during a first time interval in the power-off phase to reduce a voltage value of the second output signal.

6. The power supply circuit as claimed in claim 5, wherein the discharge circuit comprises a transistor, wherein a first terminal of the transistor is coupled to a ground terminal, and a second terminal of the transistor is used to output the second output signal, wherein the second voltage regulator further comprises a comparator, wherein the comparator is used to compare the voltage value of the input signal with the second voltage threshold to generate a comparison result signal, wherein a control terminal of the transistor is used to receive the comparison result signal, and the transistor is turned on or off according to the comparison result signal.

7. The power supply circuit as claimed in claim 5, wherein a falling rate of the second output signal in the first time interval is greater than a falling rate of the second output signal in a second time interval in the power-off phase, wherein the second time interval is later than the first time interval. 8 . The power supply circuit as claimed in claim 1 , wherein if the voltage value of the input signal is equal to or greater than the first voltage threshold during a power-on phase, the voltage value of the first output signal increases.

9. The power supply circuit as claimed in claim 8, wherein the second voltage regulator comprises: The enable terminal is used to receive the first output signal, wherein if the voltage value of the first output signal is equal to or greater than a third voltage threshold in the power-on stage, the second regulator is enabled to increase the voltage value of the second output signal. 10 . The power supply circuit as claimed in claim 9 , wherein the third voltage threshold is lower than the first voltage threshold.

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