CN-122001354-A - Intelligent door lock reset circuit and intelligent door lock

CN122001354ACN 122001354 ACN122001354 ACN 122001354ACN-122001354-A

Abstract

The invention discloses an intelligent door lock reset circuit and an intelligent door lock, and a single-tube multiplexing reset architecture based on differential pulse triggering. And the RC differential circuit is used for directly coupling a voltage step signal when the USB is inserted to drive the single triode to be instantaneously conducted. The collector electrode of the triode adopts multiplexing design, namely, on one hand, the collector electrode is connected with the enabling end of the LDO voltage stabilizer and forcibly turns off the power supply output when the LDO voltage stabilizer is conducted, and on the other hand, the path between the collector electrode and the emitter electrode when the triode is conducted is used as a discharge channel, and the residual charge of the load circuit is rapidly discharged to the ground when the triode is conducted. According to the scheme, a complex logic judgment chip is not needed, the time sequence control of 'complete power-off discharging and delayed automatic restarting' can be realized only by separating components, and the discharging loop does not consume any static power consumption in normal operation, so that the problems of incomplete resetting and power consumption of a discharging circuit in the prior art are effectively solved.

Inventors

OUYANG WEI
YE XINWEN
YU HAIYANG
LIN JIEHAO

Assignees

珠海全球时代科技股份有限公司

Dates

Publication Date: 20260508
Application Date: 20260127

Claims (11)

1. An intelligent door lock reset circuit, which is characterized by comprising: The power supply input end is used for connecting an external power supply and comprises a USB input branch; The input end of the voltage stabilizing unit is connected with the power input end, the output end of the voltage stabilizing unit is used for supplying power to the MCU and the peripheral module, the voltage stabilizing unit is provided with an enabling end for controlling the on-off of the output of the voltage stabilizing unit, the enabling end is connected to the power input end through a pull-up resistor and is configured to be kept on in a default state; The differential trigger control circuit comprises a differential capacitor, a bias resistor and a triode, wherein the differential capacitor is connected between the USB input branch and the base electrode of the triode; the controlled rapid discharge branch comprises a discharge diode and a discharge resistor which are connected in series, wherein one end of the controlled rapid discharge branch is connected with the output end of the voltage stabilizing unit, and the other end of the controlled rapid discharge branch is connected with the collector electrode of the triode; The differential trigger control circuit is configured to respond to a voltage step signal when the USB power supply is connected, and provide a conducting current for the base electrode of the triode through the differential capacitor so as to drive the triode to conduct instantaneously; The triode is configured to simultaneously perform two actions of firstly pulling down the potential of the enabling end of the voltage stabilizing unit and controlling the voltage stabilizing unit to stop outputting, and secondly conducting the controlled rapid discharging branch circuit and discharging the electric charge of the output end of the voltage stabilizing unit by utilizing a conducting path between the collector and the emitter of the triode during conducting.
2. The reset circuit of claim 1 wherein the differential trigger control circuit further comprises a current limiting resistor, the differential capacitor being connected to the base of the transistor through the current limiting resistor for limiting current through the base of the transistor.
3. The reset circuit of claim 1 wherein the positive electrode of the discharge diode is connected to the output terminal of the voltage stabilizing unit through the discharge resistor, or the positive electrode of the discharge diode is directly connected to the output terminal of the voltage stabilizing unit and the negative electrode thereof is connected to the collector of the triode through the discharge resistor; the negative side of the discharge diode is finally connected to the collector of the triode, and the unidirectional conductivity of the diode is used for preventing current from flowing backwards.
4. The reset circuit of claim 1 further comprising a reset bleed circuit comprising an input bleed resistor; One end of the input bleeder resistor is connected to one side of the differential capacitor close to the USB input branch, and the other end of the input bleeder resistor is grounded, or the input bleeder resistor is connected between the anode and the cathode of the USB power supply in parallel, and is used for bleeding charges on the differential capacitor when the USB power supply is disconnected, so that the differential circuit can generate pulses again when the USB is inserted next time.
5. The reset circuit of claim 1 wherein said power supply input further comprises a battery input branch; the battery input branch is connected to the input end of the voltage stabilizing unit through a first diode; the USB input branch is connected to the input end of the voltage stabilizing unit through a second diode; the differential capacitor is connected to the anode side of the second diode to directly sense the USB hot plug signal.
6. The reset circuit of claim 1 wherein the triode is an NPN triode or a bipolar transistor, the voltage stabilizing unit is a low dropout linear voltage regulator, and the enabling end of the low dropout linear voltage regulator is high-level active and low-level off and is connected to the power input end through an internal or external pull-up resistor; the enabling end of the voltage stabilizing unit is also connected with an enabling end filter capacitor, and the other end of the enabling end filter capacitor is grounded.
7. The reset circuit of claim 1 wherein the time constant of the differential trigger control circuit satisfies a predetermined relationship with the discharge rate of the controlled rapid discharge leg; the time constant of the bias resistor and the differential capacitor sets the conduction time of the triode, which is longer than the time required by the controlled rapid discharge branch to discharge the voltage of the output end of the voltage stabilizing unit to a safety threshold; so as to ensure that the power supply voltage of the MCU and the peripheral module is reduced below a reset level before the voltage stabilizing unit resumes output.
8. The reset circuit of claim 1 wherein the reset circuit is a pure hardware open loop control circuit; The base electrode of the triode is only connected to the differential trigger control circuit, and is not connected with the MCU or the output pin of any logic control chip; The trigger of the triode conduction is only dependent on a voltage step signal when the USB power supply is connected, and is irrelevant to the current running states of the MCU and the peripheral module and the steady-state voltage of the USB input branch.
9. The reset circuit of claim 1 wherein said controlled rapid discharge leg is in a high impedance open state when said transistor is turned off, and wherein the quiescent power consumption of said reset circuit at a non-USB insertion instant is determined by the quiescent current of said voltage stabilizing unit, excluding leakage current of said controlled rapid discharge leg.
10. The reset circuit of claim 1 wherein the transistor is a single discrete device, and wherein the differential trigger control circuit and the controlled rapid discharge leg are each comprised of discrete resistor-capacitor elements, not including an integrated circuit chip.
11. An intelligent door lock comprising a reset circuit as claimed in any one of claims 1 to 10.

Description

Intelligent door lock reset circuit and intelligent door lock Technical Field The invention relates to the technical field of electronic circuits, in particular to an intelligent door lock reset circuit and an intelligent door lock. Background With the popularization of smart home technology, smart door locks have been widely used. USB emergency power supply is a critical emergency measure when the door lock battery is exhausted or the door is abnormally dead due to software logic errors and electrostatic interference. In the prior art, a mode of controlling the MCU reset pin (ResetPin) is generally adopted. However, such "soft reset" or "logic reset" often cannot clear the dead lock state (Latch-up) inside the peripheral chip (such as fingerprint module, swipe card chip), resulting in a "dead-like" phenomenon, i.e., the peripheral still cannot work although the MCU is reset. In order to solve the problem of complete reset, the prior art has developed a scheme of restarting after power failure (such as using a MOS transistor and a capacitor charging delay circuit), or a special voltage monitoring chip is used to realize power failure detection. However, such schemes typically suffer from the following drawbacks: The circuit is complex, a multistage switching tube is often needed to be cascaded, or a main power supply loop is directly cut off, so that the cost and the internal resistance of the power supply are increased. The triggering is unreliable, the traditional level triggering mode depends on the steady state value of the USB voltage, and if the USB power supply is unstable, misoperation is easy to cause. The discharging is incomplete, and many schemes only cut off the power supply, do not provide a controlled rapid discharging channel, and cause residual charges and incomplete resetting. Static power consumption, namely continuously consuming the electric quantity of a battery if the discharging resistor is directly connected in parallel. Therefore, how to provide a circuit which does not depend on the state of the MCU, uses only extremely simple and separated components, has an unconditional hardware level complete power-off discharging function, and has zero static power consumption in a non-reset state becomes a technical problem to be solved in the art. Disclosure of Invention The invention provides an intelligent door lock reset circuit and an intelligent door lock, and aims to solve the problems of complex reset logic, low reliability and high power consumption of a discharge circuit in the prior art. The invention provides an intelligent door lock reset circuit, which comprises: The power input end is used for connecting an external power supply and comprises a USB input branch; The input end of the voltage stabilizing unit is connected with the power input end, the output end of the voltage stabilizing unit is used for supplying power to the MCU and the peripheral module, the voltage stabilizing unit is provided with an enabling end used for controlling the on-off of the output of the voltage stabilizing unit, and the enabling end is connected to the power input end through a pull-up resistor and is configured to be kept on in a default state; The differential trigger control circuit comprises a differential capacitor, a bias resistor and a triode, wherein the differential capacitor is connected between the USB input branch and the base electrode of the triode; One end of the controlled rapid discharge branch is connected with the output end of the voltage stabilizing unit, and the other end of the controlled rapid discharge branch is connected with the collector electrode of the triode; The differential trigger control circuit is configured to respond to a voltage step signal when the USB power supply is connected, and provide a conducting current for the base electrode of the triode through the differential capacitor so as to drive the triode to conduct instantaneously; the transistor is configured to control the voltage regulator unit to stop outputting by pulling its collector potential low and simultaneously to conduct the controlled rapid discharge branch to bleed off the charge at the output of the voltage regulator unit during the on period. The invention has the following remarkable beneficial effects: Single tube multiplexing, extremely simple architecture, the invention innovatively utilizes the collector of a single triode as both a "logic control point (pull low EN)" and a "power bleed point (pull low VOUT)". The design of one point dual-purpose ensures absolute synchronization of power-off and discharging while reducing the number of components, and avoids the time sequence matching risk of the multi-stage switch circuit. Edge triggering, namely capturing a voltage step signal (edge triggering) when USB is plugged in by utilizing an RC differential circuit, and not traditional level triggering. This means that the reset action only occurs at the insertion instant and the circuit