Power supply circuit and electronic equipment
By providing different voltages to the crystal oscillator circuit and the real-time clock digital circuit, the problems of inflexible power supply and high-efficiency ultra-low power consumption in the prior art are solved, and flexible and low-power power supply for the real-time clock module is realized.
Patent Information
- Application Number
- CN202423323318.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-31
- Publication Date
- 2025-12-16
- Estimated Expiration
- 2034-12-31
AI Technical Summary
Existing real-time clock modules cannot achieve flexible power supply, nor can they efficiently implement ultra-low power RTC clock circuits.
A power supply circuit including a first power supply unit and a second power supply unit is adopted to provide different voltages to the crystal oscillator circuit and the real-time clock digital circuit respectively. Differentiated power supply is achieved through a current mirror module, resistors and bias voltage generation module, and a low-pass filter can be used to stabilize the voltage.
It enables flexible power supply to the real-time clock module, reduces the power consumption of the real-time clock digital circuit, and improves the efficiency of the RTC clock circuit.
Smart Images
Figure CN223681056U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to real time clock technical field especially relates to a power supply circuit and electronic equipment. BACKGROUND
[0002] Real Time Clock (RTC) is a kind of clock circuit, commonly used in electronic equipment. Real-time clock module is powered by dedicated RTC power supply circuit under the condition of electronic equipment being closed to record time.
[0003] The existing real-time clock module usually includes 32KHz crystal oscillator circuit and real-time clock digital circuit. Crystal oscillator circuit and real-time clock digital circuit use the same RTC power supply circuit, cannot realize flexible power supply to different circuits of real-time clock module, and the power supply circuit exists bias circuit and consumes additional current, cannot efficiently realize ultra-low power consumption RTC clock circuit. SUMMARY
[0004] The utility model solves the technical problem that real-time clock module cannot be flexibly powered and ultra-low power consumption RTC clock circuit cannot be efficiently realized.
[0005] To solve the above problems, the utility model provides a power supply circuit for supplying power for real-time clock module, the real-time clock module includes crystal oscillator circuit and real-time clock digital circuit, and the power supply circuit includes first power supply unit and second power supply unit, wherein: the first end of the first power supply unit inputs power supply voltage, the second end is coupled with the crystal oscillator circuit, and the first voltage is output to the crystal oscillator circuit, the first end of the second power supply unit inputs the power supply voltage, the second end is coupled with the real-time clock digital circuit, the control end is coupled with the third end of the first power supply unit, the second voltage is output to the real-time clock digital circuit, the third end of the first power supply unit outputs the third voltage, the second voltage is associated with the third voltage, and the first voltage and the second voltage are not equal.
[0006] The power supply circuit includes first power supply unit and second power supply. The first voltage is output by the first power supply unit to power the crystal oscillator circuit, and the second voltage is output by the second power supply unit to power the real-time clock digital circuit. The first voltage and the second voltage are different, so that one power supply circuit provides different voltages for the crystal oscillator circuit and the real-time clock digital circuit respectively.
[0007] Optionally, the first power supply unit comprises a current mirror module, a first resistor and a bias voltage generation module, wherein the current mirror module comprises a reference current generation branch and a reference current mirror branch; the reference current generation branch has a first end inputting the power supply voltage and a second end coupled with a first end of the first resistor; the reference current mirror branch has a first end inputting the power supply voltage and a second end coupled with a second end of the bias voltage generation module and is adapted to mirror the reference current output by the reference current generation branch to obtain a mirror current; the first resistor has a second end coupled with the crystal oscillator circuit and a first end of the bias voltage generation module; and the bias voltage generation module has a second end outputting the third voltage.
[0008] Optionally, the current mirror module comprises a first PMOS tube and a second PMOS tube, and the bias voltage generation module comprises a third PMOS tube, wherein the first PMOS tube has a source inputting the power supply voltage, a gate coupled with a gate of the second PMOS tube and a drain coupled with the gate and a first end of the first resistor; the second PMOS tube has a source inputting the power supply voltage and a drain coupled with a source of the third PMOS tube; and the third PMOS tube has a gate coupled with a drain and a drain coupled with a second end of the first resistor.
[0009] Optionally, the first PMOS tube, the second PMOS tube and the third PMOS tube have substrates connected to the power supply.
[0010] Optionally, the first resistor is an adjustable resistance.
[0011] Optionally, the second power supply unit comprises a fourth NMOS tube, wherein the fourth NMOS tube has a drain inputting the power supply voltage, a gate coupled with an output end of the first power supply unit and a source coupled with the real-time clock digital circuit.
[0012] Optionally, the fourth NMOS tube has a substrate connected to the ground.
[0013] Optionally, the power supply circuit further comprises a low-pass filter arranged between a third end of the first power supply unit and a control end of the second power supply unit.
[0014] Optionally, the low-pass filter comprises a second resistor and a first capacitor, wherein the second resistor has a first end coupled with the third end of the first power supply unit and a second end coupled with the control end of the second power supply unit and a first end of the first capacitor; and the first capacitor has a second end connected to the ground.
[0015] In a second aspect, the utility model further provides an electronic device comprising the power supply circuit. In a second aspect, the utility model further provides an electronic device comprising the power supply circuit. BRIEF DESCRIPTION OF DRAWINGS
[0016] Figure 1 is a structure schematic diagram of an electronic device in the embodiment of the utility model;
[0017] Figure 2 is a structure schematic diagram of a power supply circuit in the embodiment of the utility model;
[0018] Figure 3 is an RC Bode diagram of a low pass filter in the embodiment of the utility model. DETAILED DESCRIPTION
[0019] As described in the above background, the crystal oscillator circuit and the real-time clock digital circuit use the same RTC power supply circuit, and cannot realize flexible power supply for different circuits of the real-time clock module.
[0020] In the embodiment of the utility model, the first power supply unit outputs the first voltage to supply power for the crystal oscillator circuit, and the second power supply unit outputs the second voltage to supply power for the real-time clock digital circuit. The power supply circuit can output the first voltage and the second voltage with different voltage values, so as to realize providing different voltages for the crystal oscillator circuit and the real-time clock digital circuit by one power supply circuit.
[0021] In order to make the above-mentioned purpose, features and advantages of the utility model more obvious and easy to understand, the specific embodiments of the utility model are described in detail below with reference to the drawings.
[0022] Referring to Figure 1 , a structure schematic diagram of an electronic device in the embodiment of the utility model is given. Referring to Figure 2 , a structure schematic diagram of a power supply circuit in the embodiment of the utility model is given. The following is described in combination with Figure 1 and Figure 2 .
[0023] In the embodiment of the utility model, the electronic device can further include an external power supply 101, a power supply circuit 102 and a real-time clock module 103. The external power supply 101 provides voltage output for the power supply circuit 102, and the power supply circuit 102 provides voltage output for the real-time clock module 103.
[0024] In the embodiment of the utility model, the real-time clock module can be a real-time clock chip, or a hardware circuit structure capable of realizing real-time clock output. The power supply circuit can be integrated in the same chip as the real-time clock module, or the power supply circuit can also be arranged in different chips from the real-time clock module.
[0025] In specific implementation, the real-time clock module can include a crystal oscillator circuit and a real-time clock digital circuit. The power supply circuit can include a first power supply unit and a second power supply unit, wherein: the first power supply unit outputs a first voltage for powering the crystal oscillator circuit; and the second power supply unit outputs a second voltage for powering the real-time clock digital circuit.
[0026] Specifically, a first end of the first power supply unit inputs a power supply voltage, and a second end of the first power supply unit is coupled with the crystal oscillator circuit; the first power supply unit outputs the first voltage through the second end;
[0027] A first end of the second power supply unit inputs the power supply voltage, a second end of the second power supply unit is coupled with the real-time clock digital circuit, and a control end of the second power supply unit is coupled with a third end of the first power supply unit; the second power supply unit outputs the second voltage through the second end; the third end of the first power supply unit outputs a third voltage; and the first voltage, the second voltage and the third voltage can all be different.
[0028] In the embodiment of the utility model, the second voltage outputted by the second power supply unit is associated with the third voltage outputted by the third end of the first power supply unit.
[0029] In specific implementation, the second voltage can be less than the third voltage, and the second voltage can be greater than the first voltage. That is, the working voltage provided by the power supply circuit for the crystal oscillator circuit is different from the working voltage provided by the power supply circuit for the real-time clock digital unit.
[0030] In the embodiment of the utility model, the first power supply unit can include: a current mirror module, a first resistor and a bias voltage generation module, wherein:
[0031] The current mirror module can include a reference current generation branch and a reference current mirror branch, wherein: a first end of the reference current generation branch inputs a power supply voltage, and a second end of the reference current generation branch is coupled with a first end of the first resistor;
[0032] A first end of the reference current mirror branch inputs the power supply voltage, and a second end of the reference current mirror branch is coupled with a second end of the bias voltage generation module; the reference current mirror branch is adapted to mirror the reference current outputted by the reference current generation branch to obtain a mirror current in a same proportion;
[0033] A second end of the first resistor is coupled with the crystal oscillator circuit and a first end of the bias voltage generation module;
[0034] The second end of the bias voltage generation module outputs the third voltage.
[0035] In some embodiments, the input power supply voltage can be 1.5V, and the reference current is less than 200 nanoamperes (nA). The mirror current can be obtained by 1:1 mirroring of the reference current, so the mirror current is also less than 200nA.
[0036] In a specific implementation, as shown in Figure 2 the current mirror module can include a first PMOS tube MP1, a second PMOS tube MP2, and the bias voltage generation module can include a third PMOS tube MP3, wherein:
[0037] The source of the first PMOS tube MP1 inputs a power supply voltage VDD, the gate of the first PMOS tube MP1 is coupled with the drain of the first PMOS tube MP1 and the gate of the second PMOS tube MP2, and the drain of the first PMOS tube MP1 is coupled with the first end of the first resistor R1;
[0038] The source of the second PMOS tube MP2 inputs the power supply voltage VDD, the gate of the second PMOS tube MP2 is coupled with the gate of the first PMOS tube MP1, and the drain of the second PMOS tube MP2 is coupled with the source of the third PMOS tube MP3;
[0039] The gate of the third PMOS tube MP3 is coupled with the drain of the third PMOS tube MP3, and the drain of the third PMOS tube MP3 is further coupled with the second end of the first resistor R1.
[0040] In a specific implementation, the first PMOS tube MP1 and the second PMOS tube MP2 are coupled with the substrate of the third PMOS tube MP3 to input the power supply voltage VDD.
[0041] In a specific implementation, the first resistor R1 is an adjustable resistor. The resistance value of the first resistor R1 can be configured by an external register or a control signal, and by configuring, the size of the first resistor R1 can be adjusted, so that the driving current input to the crystal oscillator circuit can be adjusted. The size of the driving current is adjusted according to the configuration, and the adjustment range is 20nA-200nA.
[0042] In the embodiment of the utility model, the second power supply unit can include a fourth NMOS tube MN4, wherein: the drain of the fourth NMOS tube MN4 inputs a power supply voltage VDD, the gate of the fourth NMOS tube MN4 is coupled with the output end of the first power supply unit, and the source of the fourth NMOS tube MN4 is coupled with the real-time clock digital circuit.
[0043] In a specific implementation, the substrate of the fourth NMOS tube MN4 is grounded (GND).
[0044] In the embodiment of the utility model, the fourth NMOS tube MN4 can be a native NMOS tube, which has a small conduction threshold value Vgs, usually less than 0.1V. Therefore, only a small voltage needs to be input to the gate of the fourth NMOS tube MN4 to turn it on.
[0045] In this embodiment of the invention, a low-pass filter can be provided between the third terminal of the first power supply unit and the control terminal of the second power supply unit. By providing a low-pass filter, the influence of fluctuations in the operating voltage of the crystal oscillator circuit can be filtered out, ensuring that the second power supply unit can output a stable second voltage.
[0046] In a specific implementation, the low-pass filter may include: a second resistor R2 and a first capacitor C1, wherein:
[0047] The first end of the second resistor R2 is coupled to the third end of the first power supply unit, and the second end of the second resistor R2 is coupled to the control end of the second power supply unit and the first end of the first capacitor C1.
[0048] The second terminal of the first capacitor C1 is grounded.
[0049] like Figure 2 As shown, in the low-pass filter, the first end of the second resistor R2 is coupled to the drain of the second PMOS transistor MP2 and the source of the third PMOS transistor MP3, and the second end of the second resistor R2 is coupled to the gate of the fourth NMOS transistor MN4 and the first end of the first capacitor C1.
[0050] In this embodiment of the invention, a second resistor R2 with a corresponding resistance value and a first capacitor C1 with a corresponding capacitance value can be selected based on the actual application scenario.
[0051] In some embodiments, the resistance of the second resistor R2 is 4 megohms (MΩ), and the capacitance of the first capacitor C1 is 10 picofarads (pF). The RC Bode plot of this low-pass filter is shown below. Figure 3 As shown. Figure 3 In the graph, the vertical axis represents the magnification factor (V), measured in decibels (dB); the horizontal axis represents the frequency (freq), measured in hertz (Hz).
[0052] The working principle of the power supply circuit provided in the embodiments of this utility model will be explained below.
[0053] In the first power supply unit, the gate and source of the first PMOS transistor MP1 are coupled, forming a self-biased circuit, and it operates in the saturation region. When the first PMOS transistor MP1 is turned on, there is a current output across the first resistor R1. By adjusting the resistance value of the first resistor R1, the current across the first resistor R1 can be adjusted, thereby adjusting the drive current input to the crystal oscillator circuit. Furthermore, when the first PMOS transistor MP1 is turned on, it outputs a first voltage to the crystal oscillator circuit.
[0054] The second PMOS MP2 and the first PMOS MP1 form a current mirror, and the second PMOS MP2 is in a reference current mirror image branch to copy the current generated by a reference current generating branch in proportion.
[0055] The gate of the third PMOS MP3 is coupled with the drain of the third PMOS MP3 to form a self-bias circuit, and the third PMOS MP3 works in a saturation region to form a source follower.
[0056] The output end of the second power supply branch is the output end of the fourth NMOS MN4, and the output end of the fourth NMOS MN4 is the source of the fourth NMOS MN4 to form a source follower.
[0057] As can be seen, the first power supply branch supplies power for the crystal circuit, the second power supply branch supplies power for the real-time clock digital circuit, and the first voltage is different from the second voltage.
[0058] In addition, the supply voltage of the real-time clock digital circuit can be greatly reduced, and the power consumption of the real-time clock can be reduced.
[0059] The utility model embodiment further provides an electronic equipment comprising the power supply circuit provided by any one of the above embodiments.
[0060] Although the utility model discloses as above, the utility model is not limited to this. Any person skilled in the art, without departing from the spirit and scope of the utility model, can make various changes and modifications, therefore the protection scope of the utility model should be the range defined by the claims.
Claims
1. A power supply circuit, characterized in that, This circuit is used to power a real-time clock module, which includes a crystal oscillator circuit and a real-time clock digital circuit. The power supply circuit includes a first power supply unit and a second power supply unit, wherein: The first power supply unit has a first terminal that receives a power supply voltage and a second terminal that is coupled to the crystal oscillator circuit to output a first voltage to the crystal oscillator circuit. The second power supply unit has the power supply voltage input at its first terminal, its second terminal coupled to the real-time clock digital circuit, and its control terminal coupled to the third terminal of the first power supply unit, outputting a second voltage to the real-time clock digital circuit. The third terminal of the first power supply unit outputs a third voltage, the second voltage is associated with the third voltage, and the first voltage is not equal to the second voltage.
2. The power supply circuit as described in claim 1, characterized in that, The first power supply unit includes: a current mirror module, a first resistor, and a bias voltage generation module, wherein: The current mirror module includes a reference current generation branch and a reference current mirroring branch. The reference current generation branch has the power supply voltage input at its first end and its second end coupled to the first end of the first resistor. The reference current mirroring branch has the power supply voltage input at its first end and its second end coupled to the second end of the bias voltage generation module, which is suitable for mirroring the reference current output by the reference current generation branch to obtain a mirror current. The second end of the first resistor is coupled to the first end of the crystal oscillator circuit and the bias voltage generation module. The bias voltage generation module outputs the third voltage at its second terminal.
3. The power supply circuit as described in claim 2, characterized in that, The current mirror module includes a first PMOS transistor and a second PMOS transistor, and the bias voltage generation module includes a third PMOS transistor, wherein: The first PMOS transistor has the power supply voltage input at its source, its gate is coupled to the gate of the second PMOS transistor, and its drain is coupled to its gate and the first end of the first resistor. The second PMOS transistor has the power supply voltage input at its source and its drain is coupled to the source of the third PMOS transistor. The third PMOS transistor has its gate coupled to its drain, and its drain coupled to the second end of the first resistor.
4. The power supply circuit as described in claim 3, characterized in that, The substrates of the first PMOS transistor, the second PMOS transistor, and the third PMOS transistor are all connected to a power supply.
5. The power supply circuit as described in claim 2, characterized in that, The first resistor is an adjustable resistor.
6. The power supply circuit as described in claim 1, characterized in that, The second power supply unit includes: a fourth NMOS transistor; The fourth NMOS transistor has the power supply voltage input at its drain, its gate coupled to the output terminal of the first power supply unit, and its source coupled to the real-time clock digital circuit.
7. The power supply circuit as described in claim 6, characterized in that, The substrate of the fourth NMOS transistor is grounded.
8. The power supply circuit as described in claim 1, characterized in that, Also includes: A low-pass filter is disposed between the third terminal of the first power supply unit and the control terminal of the second power supply unit.
9. The power supply circuit as described in claim 8, characterized in that, The low-pass filter includes: a second resistor and a first capacitor, wherein: The second resistor has its first end coupled to the third end of the first power supply unit, and its second end coupled to the control terminal of the second power supply unit and the first end of the first capacitor. The second terminal of the first capacitor is grounded.
10. An electronic device, characterized in that, Includes the power supply circuit as described in any one of claims 1 to 9.