DC-IN power supply misplug protection circuit on computer mainboard
By designing a DC-IN power mis-insertion protection circuit on the computer motherboard and using NPN transistors and MOSFETs to detect voltage, the problem of mis-insertion of high voltage at the DC-IN interface is solved, and the protection and alarm functions of the equipment are realized.
Patent Information
- Application Number
- CN202422401820.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-30
- Publication Date
- 2025-09-16
- Estimated Expiration
- 2034-09-30
AI Technical Summary
The DC-IN interface on existing computer motherboards is easily mistakenly plugged into a high-voltage power supply, causing damage to the device and lacking an effective protection mechanism.
A DC-IN power supply mis-insertion protection circuit is designed. It uses NPN transistors and N-channel MOSFETs to detect the voltage of the inserted power supply through a resistor network and logic control devices to achieve circuit protection function.
It effectively prevents high voltage from damaging the motherboard by detecting and preventing the device from starting up, and alarming the user when a high voltage is mistakenly inserted.
Smart Images
Figure CN223348370U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of electronic computers, in particular to a DC-IN power mis-insertion protection circuit on a computer mainboard. Background Art
[0002] Nowadays, many all-in-one computers or portable computers such as laptops still use DC-IN (direct current input power) power interfaces. However, because the size of DC-IN power interfaces is generally 2.5 or 3.5 mm, these power interfaces look the same to users, so it is easy to plug the DC power supply of one product into another product.
[0003] However, unlike the Type-C interface, the DC-IN interface has a fixed input power source, while the DC-IN interface's power supply can vary from product to product, offering 12V, 19V, or other custom voltages. Accidentally inserting a high-voltage DC-IN power source without knowing the voltage can cause the device to burn out due to the high voltage. Therefore, protection circuits are typically included in designs to prevent users from inserting a power source with a higher voltage than the rated voltage. Inserting a low-voltage power source generally won't burn the device; at most, the device won't boot or won't power up after booting. Therefore, there's no low-voltage protection.
[0004] Therefore, it is a long-standing need in the art to design a DC-IN power mis-insertion protection circuit on a computer motherboard to prevent damage to the computer motherboard when a high-voltage DC-IN power supply is mistakenly inserted. Summary of the Invention
[0005] Therefore, the purpose of the present invention is to provide a DC-IN power mis-insertion protection circuit on a computer motherboard to prevent damage to the computer motherboard when a high-voltage DC-IN power supply is mistakenly inserted.
[0006] To achieve the above-mentioned object, the present invention provides a DC-IN power mis-insertion protection circuit on a computer motherboard, comprising: an NPN transistor, an N-channel MOSFET, a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, and a seventh resistor; the base of the NPN transistor is electrically connected to the DC-IN power inserted into the motherboard via the first resistor and is grounded via the second resistor; the emitter of the NPN transistor is grounded; the collector of the NPN transistor is electrically connected to the DC-IN power inserted into the motherboard via the third resistor and is grounded via the fourth resistor; the gate of the N-channel MOSFET is electrically connected to the collector of the NPN transistor, the source is grounded, and the drain is electrically connected to a power-on enable signal output terminal via the fifth resistor; the power-on enable signal output terminal is electrically connected to a standby power supply on the motherboard via the sixth resistor and is grounded via the seventh resistor;
[0007] The resistance values of the first resistor and the second resistor are configured according to the conduction voltage of the NPN transistor, under the condition that when the voltage of the DC-IN power input is less than the maximum voltage allowed by the mainboard, the NPN transistor is not turned on, and when the voltage is greater than the maximum voltage allowed by the mainboard, the NPN transistor is turned on.
[0008] The power-on enable signal output terminal is electrically connected to a logic control device on the mainboard to inform whether power can be supplied.
[0009] Wherein, the logic control device is EC or CPLD.
[0010] Wherein, the NPN transistor is LMBT3904LT1G.
[0011] Wherein, the N-channel MOSFET is LBSS138LT1G.
[0012] The resistance of the first resistor is 24 kilo-ohms, and the resistance of the second resistor is 1 kilo-ohm.
[0013] The resistance of the third resistor is 10 kilo-ohms, and the resistance of the fourth resistor is 10 kilo-ohms.
[0014] Wherein, the standby power supply is a 3.3V standby power supply.
[0015] The resistance of the fifth resistor is 150 ohms, the resistance of the sixth resistor is 1 kilo ohm, and the resistance of the seventh resistor is 100 kilo ohms.
[0016] Wherein, the logic control device is electrically connected to the alarm on the main board.
[0017] In summary, the DC-IN power mis-insertion protection circuit on the computer motherboard of the present invention adds a voltage identification circuit. When the user inserts a high-voltage power supply, the circuit will detect it and prevent the device from starting up. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] 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.
[0019] Figure 1 This is a circuit diagram of a preferred embodiment of the DC-IN power mis-insertion protection circuit on a computer motherboard of the present invention. DETAILED DESCRIPTION
[0020] See also Figure 1, which is a circuit diagram of a preferred embodiment of the DC-IN power mis-insertion protection circuit on the computer motherboard of the utility model. In this preferred embodiment, the DC-IN power mis-insertion protection circuit on the computer motherboard mainly includes: an NPN transistor PQ12, an N-channel MOSFET PQ11, a first resistor PR205, a second resistor PR211, a third resistor PR206, a fourth resistor PR210, a fifth resistor PR207, a sixth resistor PR204, and a seventh resistor PR209; the base of the NPN transistor PQ12 is electrically connected to the DC-IN power +VDC inserted on the motherboard via the first resistor PR205 and is grounded via the second resistor PR211; the emitter of the NPN transistor PQ12 is grounded; the collector of the NPN transistor PQ12 is electrically connected to the DC-IN power +VDC inserted on the motherboard via the third resistor PR206 and is grounded via the fourth resistor PR210; the N-channel MOSFET PQ11's gate is electrically connected to the collector of NPN transistor PQ12, its source is grounded, and its drain is electrically connected to the power-on enable signal (EC_PWR_EN) output terminal via a fifth resistor PR207. This power-on enable signal (EC_PWR_EN) output terminal is electrically connected to the motherboard's standby power supply P3V3SB via a sixth resistor PR204 and to ground via a seventh resistor PR209. The power-on enable signal (EC_PWR_EN) output terminal is electrically connected to the motherboard's logic control device to indicate whether power can be applied.
[0021] In this preferred embodiment, the logic control device can be an EC or CPLD, using common motherboard configurations. Specifically, the NPN transistor PQ12 is an LMBT3904LT1G, and the N-channel MOSFET PQ11 is an LBSS138LT1G. The logic control device is also electrically connected to an alarm on the motherboard (not shown). This alarm can be an LED or buzzer, controlled by simply pulling a GPIO signal from the EC / CPLD.
[0022] In the DC-IN power mis-insertion protection circuit on a computer motherboard of the present invention, the resistance values of the first resistor PR205 and the second resistor PR211 are configured based on the conduction voltage of the NPN transistor PQ12, under the condition that the voltage of the DC-IN power supply +VDC input is less than the maximum voltage allowed by the motherboard, the NPN transistor PQ12 is not turned on, and when the voltage is greater than the maximum voltage allowed by the motherboard, the NPN transistor PQ12 is turned on.
[0023] Combine Figure 1The first resistor PR205 has a resistance of 24 kilo-ohms, and the second resistor PR211 has a resistance of 1 kilo-ohm. This solution uses the LMBT3904LT1G transistor's 0.65V turn-on voltage to pass the input power voltage through a fixed voltage divider resistor, and then determines whether the divided voltage can turn the transistor on to identify the input power voltage. As shown in the figure, the voltage output of pin 1 of the PQ12 transistor is: PQ12 conducts only when V1 reaches the transistor's conduction voltage of 0.65V. Substituting this into the above formula, we find that VDC must be at least 16.25V for this to work; otherwise, it will not conduct. The actual rated voltage can be 16V, so designing with 16.25V as a margin of error allows for design flexibility.
[0024] If a 16V power supply is plugged in, V1 = 0.64 < 0.65, and PQ12 is not conducting, so PQ11's 1pin is high, PQ11 is turned on, and the EC_PWR_EN signal is low. This signal is sent to the EC / CPLD and other logic control devices, informing them that power can be turned on normally. If a 19V power supply is plugged in, V1 = 0.76 > 0.65, PQ12 is turned on, and PQ11's 1pin is low, PQ11 is not conducting, then EC_PWR_EN is high, and this signal is sent to the EC / CPLD and other logic control devices, informing them that the power supply voltage is too high and that the device cannot be turned on, and an alarm is issued to the user.
[0025] In this preferred embodiment, the resistance of the third resistor PR206 is 10 kilo-ohms, and the resistance of the fourth resistor PR210 is 10 kilo-ohms.
[0026] In this preferred embodiment, the standby power supply P3V3SB is a 3.3V standby power supply on the main board; the resistance of the fifth resistor PR207 is 150 ohms, the resistance of the sixth resistor PR204 is 1 kiloohm, and the resistance of the seventh resistor PR209 is 100 kiloohms.
[0027] In summary, the DC-IN power mis-insertion protection circuit on the computer motherboard of the present invention adds a voltage recognition circuit. When the user inserts a high-voltage power supply, the circuit will detect it, prevent the device from starting up, and alarm to remind the user.
[0028] 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. A DC-IN power mis-insertion protection circuit on a computer motherboard, characterized in that: include: NPN transistor (PQ12), N-channel MOSFET (PQ11), a first resistor (PR205), a second resistor (PR211), a third resistor (PR206), a fourth resistor (PR210), a fifth resistor (PR207), a sixth resistor (PR204), and a seventh resistor (PR209); the base of the NPN transistor (PQ12) is electrically connected to a DC-IN power supply (+VDC) inserted into the mainboard via the first resistor (PR205) and is grounded via the second resistor (PR211); the emitter of the NPN transistor (PQ12) is grounded; the collector of the NPN transistor (PQ12) is electrically connected to a DC-IN power supply (+VDC) inserted into the mainboard via the third resistor (PR206) and is grounded via the fourth resistor (PR210); the N-channel MOSFET The gate of the SFET (PQ11) is electrically connected to the collector of the NPN transistor (PQ12), the source is grounded, and the drain is electrically connected to the output end of the power-on enable signal (EC_PWR_EN) via a fifth resistor (PR207); the output end of the power-on enable signal (EC_PWR_EN) is electrically connected to the standby power supply (P3V3SB) on the mainboard via a sixth resistor (PR204) and is grounded via a seventh resistor (PR209); the resistance values of the first resistor (PR205) and the second resistor (PR211) are configured according to the conduction voltage of the NPN transistor (PQ12), under the condition that when the voltage input by the DC-IN power supply (+VDC) is less than the maximum voltage allowed by the mainboard, the NPN transistor (PQ12) is not turned on, and when the voltage is greater than the maximum voltage allowed by the mainboard, the NPN transistor (PQ12) is turned on.
2. The DC-IN power mis-insertion protection circuit on a computer motherboard according to claim 1, characterized in that: The power-on enable signal (EC_PWR_EN) output terminal is electrically connected to a logic control device on the mainboard to inform whether power can be supplied.
3. The DC-IN power mis-insertion protection circuit on a computer motherboard according to claim 2, wherein: The logic control device is EC or CPLD.
4. The DC-IN power mis-insertion protection circuit on a computer motherboard according to claim 1, wherein: The NPN transistor (PQ12) is LMBT3904LT1G.
5. The DC-IN power mis-insertion protection circuit on a computer motherboard according to claim 1, wherein: The N-channel MOSFET (PQ11) is LBSS138LT1G.
6. The DC-IN power mis-insertion protection circuit on a computer motherboard according to claim 4, characterized in that: The resistance of the first resistor (PR205) is 24 kilo-ohms, and the resistance of the second resistor (PR211) is 1 kilo-ohm.
7. The DC-IN power mis-insertion protection circuit on a computer motherboard according to claim 6, characterized in that: The resistance of the third resistor (PR206) is 10 kilo-ohms, and the resistance of the fourth resistor (PR210) is 10 kilo-ohms.
8. The DC-IN power mis-insertion protection circuit on a computer motherboard according to claim 1, wherein: The standby power supply (P3V3SB) is a 3.3V standby power supply.
9. The DC-IN power mis-insertion protection circuit on a computer motherboard as claimed in claim 8, characterized in that: The resistance of the fifth resistor (PR207) is 150 ohms, the resistance of the sixth resistor (PR204) is 1 kilo ohm, and the resistance of the seventh resistor (PR209) is 100 kilo ohms.
10. The DC-IN power mis-insertion protection circuit on a computer motherboard according to claim 2, wherein: The logic control device is electrically connected to the alarm on the main board.