Startup and shutdown protection device of mobile DR
By introducing switch control circuits and drive monitoring circuits into the mobile DR, surge current is alleviated, solving the problems of large size and high cost of traditional surge protection circuits, and achieving system stability and component protection.
Patent Information
- Application Number
- CN202423158986.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-20
- Publication Date
- 2025-09-16
- Estimated Expiration
- 2034-12-20
AI Technical Summary
In the existing mobile DR surge protection circuit, the traditional surge suppression module is large and costly, and the current limiting effect of the NTC thermistor is greatly affected by the ambient temperature, resulting in a high risk of component damage and poor system stability.
A switch control circuit including resistors, capacitors, MOS tubes and transistors is used, combined with a drive monitoring circuit. The conduction of the MOS tube is controlled by detecting the input voltage, thereby alleviating surge impact current and avoiding damage to components.
It improves the stability of the system, reduces the failure rate, protects components, and increases the service life and reliability of the product.
Smart Images
Figure CN223348368U_ABST
Abstract
Description
Technical Field
[0001] The utility model belongs to the technical field of mobile DR, and in particular relates to a power on / off protection device of a mobile DR. Background Art
[0002] The integration of digital technology and X-ray imaging has enabled widespread application of digital X-rays. This has led to the emergence of mobile bedside digital radiography. Existing X-ray machines are available in both fixed and mobile versions. Mobile DR (Double Detector) has ushered in a new era of digital bedside radiography, meeting the needs of patients in ICUs, emergency rooms, and wards, making it an indispensable mobile medical device in hospitals. Surge protection circuits are essential for mobile DR development. They address peak currents or overload currents that exceed the steady-state current at power-on or during circuit anomalies. Inrush currents can reach over 300A during power-on, which can easily damage components and cause circuit malfunctions. Traditional surge suppression modules in surge protection circuits are bulky and costly. The current-limiting effectiveness of NTC thermistors is significantly affected by ambient temperature. If the resistance is too high and the charging current is too low during low-temperature startup, the switching power supply may fail to start. If the thermistor's resistance is too low during startup at high temperatures, the input inrush current may not be effectively limited. Summary of the Invention
[0003] In view of this, the purpose of the present invention is to provide a mobile DR power on / off protection device, aiming to solve the above-mentioned technical problems existing in the prior art.
[0004] The purpose of the utility model can be achieved through the following technical solutions: A mobile DR power on / off protection device, including a power front end, a switch control circuit and a power back end, the power front end is connected to the input end of the switch control circuit, the output end of the switch control circuit is connected to the power back end, the controlled end of the switch control circuit is connected to a drive monitoring circuit, an input voltage detection circuit is connected between the power front end and the switch control circuit, and the input voltage detection circuit is connected to the signal input end of the drive monitoring circuit; the drive monitoring circuit is used to control the switch control circuit to be turned on according to the input voltage value detected by the input voltage detection circuit when it detects that the power front end inputs power to the input end of the switch control circuit, so as to output power to the power back end.
[0005] Preferably, the drive monitoring circuit includes a single chip microcomputer and its peripheral circuits, and the input voltage detection circuit is a voltage detection resistor.
[0006] Preferably, the switch control circuit includes a resistor R1, a resistor R2, a resistor R3, a capacitor C, a MOS transistor Q1, and a transistor Q2. The first end of the resistor R1 and the source of the MOS transistor Q1 are both connected to the front end of a power supply. The capacitor C is connected across the source and gate of the MOS transistor Q1. The first end of the resistor R2 is connected to the gate of the MOS transistor Q1. The second end of the resistor R1 and the second end of the resistor R2 are both connected to the collector of the transistor Q2. The base of the transistor Q2 is connected to the first end of the resistor R3. The second end of the resistor R3 is connected to the output end of the drive monitoring circuit. The emitter of the transistor Q2 is grounded.
[0007] Preferably, the switch control circuit further includes a resistor R4, a first end of which is connected to the second end of the resistor R3, and a second end of which is grounded. R4 acts as a pull-down resistor to ensure circuit stability and eliminate noise.
[0008] Preferably, the MOS transistor Q is an insulated gate enhancement type P-MOS transistor, and the transistor Q2 is an NPN transistor.
[0009] Compared with the existing technology, the present invention has the following advantages: it solves the surge problem in the circuit through the amplification characteristics and low-impedance overcurrent capability of the MOS tube, avoids the large current generated by the instantaneous short-circuit characteristics of the output side capacitor; improves the stability of system use, prevents components from being damaged by impact current, reduces the failure rate of the product and improves the quality of the product. BRIEF DESCRIPTION OF THE DRAWINGS
[0010] Figure 1 1 is a principle block diagram of the on / off protection device of the mobile DR in the embodiment.
[0011] Figure 2 2 is a schematic diagram of the circuit principle of the switch control circuit in the embodiment. DETAILED DESCRIPTION
[0012] The following are specific embodiments of the present invention and the accompanying drawings to further describe the technical solution of the present invention, but the present invention is not limited to these embodiments.
[0013] like Figure 1 、 2As shown, the mobile DR power on / off protection device provided by the present invention includes a power front end, a switch control circuit and a power back end. The power front end is connected to the input end of the switch control circuit, the output end of the switch control circuit is connected to the power back end, the controlled end of the switch control circuit is connected to the drive monitoring circuit, an input voltage detection circuit is connected between the power front end and the switch control circuit, and the input voltage detection circuit is connected to the signal input end of the drive monitoring circuit; the drive monitoring circuit is used to control the switch control circuit to be turned on according to the input voltage value detected by the input voltage detection circuit when it detects that the power front end inputs power to the input end of the switch control circuit, so as to output power to the power back end.
[0014] The drive monitoring circuit includes a single-chip microcontroller and its peripheral circuits, and the input voltage detection circuit is a voltage detection resistor. The drive monitoring circuit outputs a low-level or high-level signal to the switch control circuit to control the conduction and shutdown of the switch control circuit.
[0015] Specifically, such as Figure 2 As shown, the switch control circuit includes resistors R1, R2, R3, capacitor C, MOS transistor Q1, and transistor Q2. The first end of resistor R1 and the source of MOS transistor Q1 are both connected to the front end of the power supply. Capacitor C is connected between the source and gate of MOS transistor Q1. The first end of resistor R2 is connected to the gate of MOS transistor Q1. The second ends of resistor R1 and R2 are both connected to the collector of transistor Q2. The base of transistor Q2 is connected to the first end of resistor R3. The second end of resistor R3 is connected to the output of the drive monitoring circuit. The emitter of transistor Q2 is grounded. In this embodiment, MOS transistor Q is an insulated gate enhancement type P-MOS transistor, and transistor Q2 is an NPN transistor.
[0016] The switch control circuit also includes a resistor R4, a first end of which is connected to the second end of resistor R3, and a second end of which is grounded. R4 acts as a pull-down resistor to ensure circuit stability and eliminate noise.
[0017] The principle of this utility model is as follows:
[0018] The driver monitoring circuit collects the power signal from the power supply front end and outputs a control signal to the MOS transistor switching circuit. When the power supply front end is not powered on or has just been powered on, the low-level signal output by the driver monitoring circuit pulls the base of transistor Q2 to ground, making it non-conductive. Consequently, the Vgs of MOS transistor Q1 is zero, making MOS transistor Q1 non-conductive and resulting in no output from the power supply back end. Resistor R4 holds the base of transistor Q2 at a low level to prevent it from floating when the control signal output by the driver monitoring circuit is high impedance.
[0019] When the drive monitoring circuit detects that the power front end has been powered on, the voltages across the G and S terminals of the MOS tube Q1 are equal, and Vgs is still zero. At this time, the drive monitoring circuit outputs a high-level signal, the transistor Q2 is turned on, and the capacitor C1 and the resistor R2 are charged. That is, the voltage at the terminal connected to the G terminal of the capacitor C1 and the MOS tube Q1 slowly drops to 0V, causing the Vgs voltage to gradually increase. The MOS tube Q1 is slowly turned on until it is fully turned on. The charging time of the capacitor C1 is used to achieve the slow turn-on of the MOS tube Q1, thereby suppressing the surge impact caused by the excessive current at the startup moment.
[0020] The specific embodiments described herein are merely illustrative of the spirit of the present invention. Persons skilled in the art may make various modifications, additions, or substitutions to the described specific embodiments without departing from the spirit of the present invention or exceeding the scope defined by the appended claims.
Claims
1. A mobile DR power on / off protection device, characterized in that: The power supply comprises a power front end, a switch control circuit and a power back end, wherein the power front end is connected to the input end of the switch control circuit, the output end of the switch control circuit is connected to the power back end, the controlled end of the switch control circuit is connected to the drive monitoring circuit, an input voltage detection circuit is connected between the power front end and the switch control circuit, and the input voltage detection circuit is connected to the signal input end of the drive monitoring circuit; The drive monitoring circuit is used to control the switch control circuit to conduct according to the input voltage value detected by the input voltage detection circuit when it detects that the power front end inputs power to the input end of the switch control circuit, so as to output power to the power back end.
2. The mobile DR on / off protection device according to claim 1, characterized in that: The drive monitoring circuit includes a single chip microcomputer and its peripheral circuits, and the input voltage detection circuit is a voltage detection resistor.
3. A mobile DR on / off protection device according to claim 1 or 2, characterized in that: The switch control circuit includes a resistor R1, a resistor R2, a resistor R3, a capacitor C, a MOS transistor Q1, and a transistor Q2. The first end of the resistor R1 and the source of the MOS transistor Q1 are both connected to the front end of a power supply. The capacitor C is connected across the source and gate of the MOS transistor Q1. The first end of the resistor R2 is connected to the gate of the MOS transistor Q1. The second end of the resistor R1 and the second end of the resistor R2 are both connected to the collector of the transistor Q2. The base of the transistor Q2 is connected to the first end of the resistor R3. The second end of the resistor R3 is connected to the output end of the drive monitoring circuit. The emitter of the transistor Q2 is grounded.
4. The mobile DR on / off protection device according to claim 3, characterized in that: The switch control circuit further includes a resistor R4 , a first end of the resistor R4 is connected to the second end of the resistor R3 , and a second end of the resistor R4 is grounded.
5. The mobile DR on / off protection device according to claim 4, characterized in that: The MOS transistor Q is an insulated gate enhancement type P-MOS transistor, and the transistor Q2 is an NPN transistor.