Anti-self-locking circuit of power supply module on computer mainboard

Abstract

The utility model relates to an anti-self-locking circuit of a power supply module on a computer mainboard. The circuit is characterized in that a power supply (P5VSB) input by a power adapter is electrically connected with an input node, and the input node is electrically connected with a power supply input pin (VIN) of a power supply IC (PU3); the base electrode of the NPN type triode (PQ49) is electrically connected with the input node through a first resistor (PR10) and is grounded through a second resistor (PR17); the emitter of the NPN type triode (PQ12) is grounded, and the collector of the NPN type triode (PQ12) is electrically connected with the input node through a third resistor (PR11); a grid electrode of the N-channel MOS tube (PQ33) is electrically connected with a collector electrode of the NPN-type triode (PQ49), a source electrode of the N-channel MOS tube (PQ33) is grounded, and a drain electrode of the N-channel MOS tube (PQ33) is electrically connected with an enable signal pin (EN) of the power supply IC (PU3); and the enable signal pin (EN) is electrically connected with the input node through a fourth resistor (PR9) and is grounded through a fifth resistor (PR15). According to the utility model, self-locking of the power supply IC on the mainboard caused by factors such as plugging and unplugging of the power adapter can be prevented.

Description

Technical Field

[0001] The utility model relates to the technical field of electronic computers, in particular to an anti-self-locking circuit of a power module on a computer mainboard. Background Art

[0002] Since the power output channels of the power adapter used for the electronic computer motherboard are limited and do not meet the timing requirements of the motherboard, the power input from the power adapter to the motherboard must generally be converted by the power IC on the motherboard to meet the timing and output channel requirements of the motherboard.

[0003] If the input of the first-stage power IC on the motherboard is powered by the power adapter, the enable signal of this power IC has no other source and can only be shared with the VIN output of the power adapter, forming the standby power for other power ICs. Because the two pins of the plug and the internal contactor of the socket will cause friction and poor contact when the power adapter is plugged in and out while powered, the input level and quality cannot be well controlled, which may cause a voltage drop when powering on or off. When the drop value reaches a certain level, because the enable signal is still in the high state, the power controller will think that the power IC input is undervoltage during operation, and the input undervoltage protection will be triggered. Summary of the Invention

[0004] Therefore, the purpose of the present invention is to provide an anti-self-locking circuit for the power module on a computer motherboard to solve the technical problem of self-locking of the power IC undervoltage protection caused by unstable input voltage of the power adapter.

[0005] To achieve the above objectives, the present invention provides an anti-self-locking circuit for a power module on a computer motherboard, comprising: a power supply input from a power adapter, an NPN-type transistor, an N-channel MOS transistor, a power supply IC, a first resistor, a second resistor, a third resistor, a fourth resistor, and a fifth resistor; the power supply input from the power adapter is electrically connected to an input node, which is electrically connected to a power input pin of the power supply IC; the base of the NPN-type transistor is electrically connected to the input node via the first resistor and to ground via the second resistor; the emitter of the NPN-type transistor is grounded, and the collector is electrically connected to the input node via the third resistor; the gate of the N-channel MOS transistor is electrically connected to the collector of the NPN-type transistor, the source is grounded, and the drain is electrically connected to an enable signal pin of the power supply IC; the enable signal pin is electrically connected to the input node via the fourth resistor and to ground via the fifth resistor;

[0006] The resistance values of the first resistor and the second resistor are configured according to the turn-on voltage of the NPN transistor, under the condition that the NPN transistor is turned off when the voltage at the input node is less than the design value and is turned on when the voltage is greater than the design value.

[0007] The power input from the power adapter is electrically connected to the input node via a magnetic bead.

[0008] Wherein, a capacitor is further included, one end of the capacitor is electrically connected to the enable signal pin of the power IC, and the other end is grounded.

[0009] Wherein, a sixth resistor is further included, and the drain of the N-channel MOS tube is electrically connected to the enable signal pin of the power IC via the sixth resistor.

[0010] Wherein, the NPN transistor is LMBT3904LT1G.

[0011] Wherein, the N-channel MOS transistor is LBSS138LT1G.

[0012] Wherein, the power supply IC is TMI3113H2D.

[0013] The resistance of the first resistor is 3.24 kilo-ohms, and the resistance of the second resistor is 665 ohms.

[0014] Wherein, the resistance of the third resistor is 10 kilo-ohms.

[0015] The resistance of the fourth resistor is 20 kilo-ohms, and the resistance of the fifth resistor is 20 kilo-ohms.

[0016] In summary, the anti-self-locking circuit of the power module on the computer motherboard of the present invention can prevent the power IC on the motherboard from self-locking due to factors such as plugging and unplugging the power adapter, reduce the risk of power IC self-locking, and avoid the electronic computer motherboard from not starting up due to the power IC self-locking. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The following detailed description of the specific embodiments of the present invention in conjunction with the accompanying drawings will make the technical solutions and other beneficial effects of the present invention apparent.

[0018] Figure 1 This is a circuit diagram of a preferred embodiment of the anti-self-locking circuit of the power module on the computer motherboard of the utility model. DETAILED DESCRIPTION

[0019] See also Figure 1, which is a circuit diagram of a preferred embodiment of the anti-self-locking circuit of the power module on the computer motherboard of the utility model. In this preferred embodiment, the anti-self-locking circuit of the power module on the computer motherboard mainly includes: a power supply P5VSB input from a power adapter, an NPN transistor PQ49, an N-channel MOS transistor PQ33, a power supply IC PU3, a first resistor PR10, a second resistor PR17, a third resistor PR11, a fourth resistor PR9, and a fifth resistor PR15; the power supply P5VSB input from the power adapter is electrically connected to an input node, which is electrically connected to a power input pin VIN of the power supply IC PU3; the base of the NPN transistor PQ49 is electrically connected to the input node via the first resistor PR10 and to ground via the second resistor PR17; the emitter of the NPN transistor PQ12 is grounded, and the collector is electrically connected to the input node via the third resistor PR11; the gate of the N-channel MOS transistor PQ33 is electrically connected to the collector of the NPN transistor PQ49, the source is grounded, and the drain is electrically connected to the power supply IC The enable signal pin EN of PU3 is electrically connected to the input node via a fourth resistor PR9 and is grounded via a fifth resistor PR15.

[0020] In order to solve the problem that the input level and quality of the power adapter cannot be well controlled when the power adapter is plugged in and out under power, the power controller will think that the input of the power IC is under voltage during operation, which will cause the input undervoltage protection. Figure 1 In the circuit shown, P5VSB is the power output from the power adapter. It provides the power input VIN to the power IC and also divides the voltage through a resistor divider to provide the EN enable signal to the IC. Two stages of control circuitry are added before the EN enable signal. The first stage uses an NPN transistor PQ49, which controls the gate voltage of an N-channel MOSFET PQ33. The second stage uses an N-channel MOSFET PQ33, which controls the EN enable signal voltage, which is also key to preventing self-locking. When the power adapter input voltage does not reach the designed value, the transistor's base is low and the MOSFET's gate is high. The EN enable signal is pulled low by the ground-connected MOSFET, and the power IC does not operate. When the input voltage reaches the designed value, the transistor's base is high, pulling the MOSFET's gate low. The MOSFET then stops pulling the EN enable signal low, and the EN enable signal is high. The voltage divider divides the power adapter output voltage P5VSB to 2.5V through the resistor divider, and the power IC begins operating.

[0021] This solution effectively solves the problem of self-locking undervoltage protection of the power supply IC caused by unstable input voltage. When the input voltage is undervoltage, the base voltage of the transistor PQ49 will decrease accordingly due to voltage division, causing the transistor to be turned off. At this time, the gate of the MOS tube PQ33 is no longer pulled down by the transistor, and the gate voltage will follow the input voltage to a high level, causing the MOS tube PQ33 to turn on, pulling down the EN enable signal, and the power supply IC to turn off. The protection will not be triggered, and the power supply IC can still work normally when the EN signal is given again.

[0022] In this preferred embodiment, the model of the NPN transistor PQ49 is LMBT3904LT1G; the model of the N-channel MOS transistor PQ33 is LBSS138LT1G; and the model of the power IC PU3 is TMI3113H2D.

[0023] In this preferred embodiment, the power P5VSB input from the power adapter is electrically connected to the input node via the magnetic bead PFB2. The magnetic bead PFB2 is a 120 ohm / 5A magnetic bead used to filter the P5VSB input power.

[0024] PR10 and PR17 are resistors that divide the base voltage of transistor PQ49 and are crucial for designing the input voltage threshold. When the voltage at the power input pin VIN of the power supply IC (i.e., the power adapter's output, P5VSB) reaches the designed value (the 0.65V threshold that turns on transistor PQ49 after being divided by resistors PR10 and PR17, which in this example is 3.817V), P5VSB continues to rise, pulling down the gate of PQ33, turning it off and raising the EN enable signal. In this preferred embodiment, the resistance of the first resistor PR10 is 3.24 kilo-ohms, and the resistance of the second resistor PR17 is 665 ohms.

[0025] PR11 is the isolation resistor between VIN and the gate of MOS tube PQ33. When transistor PQ49 is in the on state, the gate of the MOS tube will be pulled low to ground. At this time, the isolation resistor PR11 can effectively isolate the input power supply P5VSB and GND, preventing the input power supply from being pulled low or affecting the quality of the input power supply; the resistance of PR11 is 10 kilo-ohms.

[0026] One end of capacitor PC30 is electrically connected to the enable signal pin EN of power IC PU3, and the other end is grounded. Capacitor PC30 is used to slow down the EN enable signal to prevent the EN enable signal from rising too fast, and can also be used to absorb jitter.

[0027] The voltage divider resistors PR9 and PR15 are used to divide the voltage of the EN source signal P5VSB. Here, the EN voltage is designed to be divided to 2.5V. The EN turn-on threshold of TMI3113H2D is 1.5V.

[0028] In this preferred embodiment, the drain of the N-channel MOS transistor PQ33 is electrically connected to the enable signal pin EN of the power IC via the sixth resistor PR12, which has a resistance of 1 kilohm. The fourth resistor PR9 has a resistance of 20 kilohm, and the fifth resistor PR15 has a resistance of 20 kilohm.

[0029] The circuit of the utility model is composed of a voltage-dividing resistor, a transistor and a MOS tube. The transistor and the MOS tube form an anti-self-locking circuit. When the power of the power adapter is unstable due to plugging and unplugging, resulting in undervoltage of the VIN of the power IC, the anti-self-locking circuit composed of the transistor and the MOS tube will preferentially turn off the EN enable signal, so that the entire power IC will stop working. The EN enable signal will not be given again until the input VIN stabilizes, so that the power IC will work again instead of entering a protection state or a self-locking state, thereby preventing the motherboard from not starting up due to the self-locking of the power IC.

[0030] The specifications of the components in the circuit of the utility model can be flexibly adjusted according to different voltage sources; the EN enable signal of the power supply chip responds quickly to the change of the power input VIN, reducing the delay time and the risk of self-locking of the power supply IC; it can be applied to circuits with different input voltages, and can be applied to circuits with different input voltages by changing the voltage divider resistor.

[0031] When designing for a specific application, the resistance values of the first resistor PR10 and the second resistor PR17 are configured according to the turn-on voltage of the NPN transistor PQ49, with the condition that the NPN transistor PQ49 is turned off when the voltage at the input node is less than the design value and is turned on when the voltage is greater than the design value.

[0032] by Figure 1 Take the circuit diagram shown as an example to illustrate the specific design ideas:

[0033] The input power supply is 5V, and the power supply IC is TMI3113H2D. The normal timing is that VIN is powered on first, and then the EN enable signal is enabled. When the EN enable signal level reaches the threshold of 1.5V, the power supply IC will start to work and output SW. The inductor and capacitor at the back end will filter the output. The base voltage threshold of the transistor PQ49 is Vbe = 0.65V, and the base voltage divider resistors of the transistor are PR10 = 3.24KΩ and PR17 = 0.665KΩ. According to the voltage divider formula:

[0034] get:

[0035]

[0036] It can be concluded that in order to turn on transistor PQ49, VIN must rise to at least 3.817V. The input undervoltage protection threshold of the power supply IC is an input voltage below 2.5V, so it can well ensure that the undervoltage protection of the power supply IC will not be triggered.

[0037] The utility model can be applied to circuit motherboards with uncontrollable input power due to factors such as plugging and unplugging, and is mainly applied to motherboards with single-channel power input to prevent the power IC on the motherboard from self-locking due to factors such as plugging and unplugging, but is not limited to such models.

[0038] In summary, the anti-self-locking circuit of the power module on the computer motherboard of the present invention can prevent the power IC on the motherboard from self-locking due to factors such as plugging and unplugging the power adapter, reduce the risk of power IC self-locking, and avoid the electronic computer motherboard from not starting up due to the power IC self-locking.

[0039] As described above, for ordinary technicians in this field, various other corresponding changes and modifications can be made according to the technical solution and technical concept of the utility model, and all these changes and modifications should fall within the scope of protection of the claims attached to the utility model.

Claims

1. An anti-self-locking circuit for a power module on a computer motherboard, characterized in that: include: A power supply (P5VSB) input from a power adapter, an NPN transistor (PQ49), an N-channel MOS transistor (PQ33), a power supply IC (PU3), a first resistor (PR10), a second resistor (PR17), a third resistor (PR11), a fourth resistor (PR9), and a fifth resistor (PR15); the power supply (P5VSB) input from the power adapter is electrically connected to an input node, and the input node is electrically connected to a power input pin (VIN) of the power supply IC (PU3); the base of the NPN transistor (PQ49) is electrically connected to the input node via the first resistor (PR10) and to ground via the second resistor (PR17); the emitter of the NPN transistor (PQ12) is grounded, and the collector is connected via The third resistor (PR11) is electrically connected to the input node; the gate of the N-channel MOS transistor (PQ33) is electrically connected to the collector of the NPN transistor (PQ49), the source is grounded, and the drain is electrically connected to the enable signal pin (EN) of the power supply IC (PU3); the enable signal pin (EN) is electrically connected to the input node via the fourth resistor (PR9) and is grounded via the fifth resistor (PR15); the resistance values of the first resistor (PR10) and the second resistor (PR17) are configured according to the turn-on voltage of the NPN transistor (PQ49), under the condition that when the voltage at the input node is less than a design value, the NPN transistor (PQ49) is turned off, and when the voltage is greater than the design value, the NPN transistor (PQ49) is turned on.

2. The anti-self-locking circuit of the power module on the computer motherboard according to claim 1, characterized in that: The power supply (P5VSB) input by the power adapter is electrically connected to the input node via a magnetic bead (PFB2).

3. The anti-self-locking circuit of the power module on the computer motherboard according to claim 1, characterized in that: The device further comprises a capacitor (PC30), one end of which is electrically connected to an enable signal pin (EN) of the power supply IC (PU3), and the other end of which is grounded.

4. The anti-self-locking circuit of the power module on the computer motherboard according to claim 1, characterized in that: A sixth resistor (PR12) is also included, and the drain of the N-channel MOS tube (PQ33) is electrically connected to the enable signal pin (EN) of the power supply IC (PU3) via the sixth resistor (PR12).

5. The anti-self-locking circuit of the power module on the computer motherboard according to claim 1, characterized in that: The NPN transistor (PQ49) is LMBT3904LT1G.

6. The anti-self-locking circuit of the power module on the computer motherboard according to claim 1, characterized in that: The N-channel MOS tube (PQ33) is LBSS138LT1G.

7. The anti-self-locking circuit of the power module on the computer motherboard according to claim 1, characterized in that: The power supply IC (PU3) is TMI3113H2D.

8. The anti-self-locking circuit of the power module on the computer motherboard according to claim 5, characterized in that: The resistance of the first resistor (PR10) is 3.24 kilo-ohms, and the resistance of the second resistor (PR17) is 665 ohms.

9. The anti-self-locking circuit of the power module on the computer motherboard according to claim 6, characterized in that: The resistance of the third resistor (PR11) is 10 kilo-ohms.

10. The anti-self-locking circuit of the power module on the computer motherboard according to claim 6, characterized in that: The resistance of the fourth resistor (PR9) is 20 kilo-ohms, and the resistance of the fifth resistor (PR15) is 20 kilo-ohms.

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