Input power control and protection

Abstract

The present disclosure relates to input power control and protection. The present disclosure describes a system and method for protecting electronic devices from high voltages that can exceed the tolerance limits of circuits within the electronic devices. A protection circuit prevents high voltages from device components through gating techniques. Such gating techniques can similarly be used to control whether an electronic component receives power when a control unit detects an error condition.

Description

Technical Field

[0001] This disclosure relates to input power control and protection. Background Technology

[0002] Wearable products are typically small, physically compact housings with elegant industrial designs. The circuitry within such products often has voltage input limitations. A typical voltage supplied by a USB Type-A charging cable might be around 5V, which is likely within the voltage input limit. However, other USB Type-C power supplies, such as those compliant with PD Type-C, may deliver up to 20V after negotiation, potentially exceeding the circuit's voltage input limit. Such excessive power delivery can damage the circuitry and the wearable product. Summary of the Invention

[0003] This disclosure provides input voltage protection without blocking the power path. Specifically, an AC signal is used to turn off transistors coupled across the power path, preventing power from flowing through the transistors. Such transistors can also be turned off in response to receiving a voltage exceeding a predetermined threshold.

[0004] One aspect of this disclosure provides a voltage protection circuit for an electronic device, including a control line coupled to a first transistor, an input power line, and a power interruption transistor coupled across the input power line and electrically coupled to the first transistor, wherein receiving a square wave signal at the first transistor via the control line causes the power interruption transistor to turn off, thereby interrupting the power flow on the input power line.

[0005] The voltage protection circuit may further include a capacitor coupled across the junction of the first transistor, wherein receiving a square wave signal from the first transistor causes the capacitor to drain. The circuit may further include a second transistor coupled between the capacitor and the power interruption transistor, wherein the second transistor is turned on when the capacitor is drained. When the second transistor is turned on, the power interruption transistor is turned off.

[0006] According to some examples, the voltage protection circuit may further include a resistor coupled between the power line input and the second transistor, the resistor having an ohmic value based on the voltage tolerance limit of the electronic device, wherein the reception of a voltage exceeding the threshold triggers the activation of the second transistor.

[0007] According to some examples, the control line can be coupled to the control unit and receive a square wave signal from the control unit in response to an error being detected.

[0008] Another aspect of this disclosure provides an electronic device including an input port, electronic components, and a voltage protection circuit located between the input port and the electronic components. The voltage protection circuit includes a control line coupled to a first transistor, an input power line, and a power interruption transistor coupled across the input power line and electrically coupled to the first transistor, wherein receiving a square wave signal at the first transistor via the control line causes the power interruption transistor to turn off, thereby interrupting the power flow on the input power line.

[0009] Another aspect of this disclosure provides a method of operating an electronic device, comprising: receiving a voltage at a power line of the electronic device coupled between an input section of the electronic device and circuitry; detecting an error condition at a controller unit; and, in response to detecting the error condition, transmitting a square wave signal via a control line to a first transistor, the square wave signal causing a power interruption transistor to turn off, the power interruption transistor preventing the circuitry of the electronic device from receiving voltage. Transmitting the square wave signal can discharge a capacitor coupled across the first transistor. Discharging the capacitor can activate a second transistor, the activation of which causes the power interruption transistor to turn off.

[0010] According to some examples, the control line remains stable when the control unit does not detect an error condition.

[0011] According to some examples, the method may further include activating a second transistor when the received voltage exceeds a predetermined threshold. Even further, the method may include turning off the second transistor when the received voltage no longer exceeds the predetermined threshold. Attached Figure Description

[0012] Figure 1A This is a functional block diagram illustrating an example system according to aspects of this disclosure.

[0013] Figure 1B yes Figure 1A Example diagram of the system.

[0014] Figure 2 These are example circuit diagrams based on aspects of this disclosure.

[0015] Figure 3 This is a flowchart illustrating an example method according to an aspect of this disclosure.

[0016] Figure 4 This is a flowchart illustrating an example method according to an aspect of this disclosure. Detailed Implementation

[0017] This disclosure describes systems and methods for protecting electronic devices from high voltages that may exceed the permissible limits of circuitry within the electronic device. The protection circuitry uses gating techniques to block high voltages from device components. Such gating techniques can be similarly used to control whether power is received by electronic components when a control unit detects a fault condition.

[0018] Example System

[0019] Figures 1A to 1B An example of a power supply 110 supplying power to an electronic device 160 is shown. For example, the power supply 110 can be powered via a cable 150, such as a charging cable. In some examples, the charging cable can be connected via an intermediate device, such as a charging brick 112 plugged into a wall socket, a laptop computer, or other computing device connected to the power supply.

[0020] The power source 110 can be, for example, a battery, a power outlet, a computing device, or any other type of device capable of supplying voltage to another device.

[0021] Cable 150 can be, for example, a USB cable or any other type of cable capable of delivering voltage from power source 110 to electronic device 160. The cable may include any of a variety of connector types at either end, such as USB-A, USB-C, micro-USB, mini-USB, 8-pin Lightning, etc.

[0022] Electronic device 160 can be any type of electronic device, including wearable devices such as earbuds 164, smartwatches, headphones, smart glasses, smart helmets, rings, pendants, clothing, etc., or non-wearable devices such as telephones, home assistant devices, displays, speakers, etc. According to some examples, electronic device 160 may include a housing 166. For example, housing 166 may be used to house the electronic accessory, such as earbuds 164, when it is not in use. Furthermore, housing 166 may be used to deliver electrical charge to the accessory. For example, the accessory may include electrical contacts that establish an electrical connection with the housing when the accessory is housed within it. Additionally, voltage supplied from power source 110 to the accessory via charging cable 150 may be supplied through the housing. For example, housing 166 may include an input for receiving charging cable 150, and a means to relay charge received from power source 110 to earbuds 164. According to some examples, housing 166 may include a battery, capacitor, or electronic components for storing charge from power source 110 for later charging of earbud 164 when earbud 164 is housed within housing 166 but charging cable 150 is no longer connected. Although Figure 1B The example shows an earbud inside the housing, but it should be understood that electronic device 160 may include any one of a plurality of electronic devices, including wearable and non-wearable electronic devices.

[0023] Electronic device 160 may include one or more processors 130, one or more memories 120, and other components. For example, electronic device 160 may include a battery 162.

[0024] Memory 120 may store information accessible to one or more processors 130, including data 122 and instructions 128 that can be executed or otherwise used by one or more processors 130. For example, memory 120 may be any type capable of storing information accessible to a processor, including computing device readable media or other media storing data that can be read by means of an electronic device, such as volatile memory, non-volatile memory, and other writable and read-only memories. By way of example only, memory 120 may be static random access memory (SRAM) configured to provide fast lookup. Systems and methods may include different combinations of the foregoing, whereby different portions of instructions and data are stored on different types of media.

[0025] Data 122 can be retrieved, stored, or modified by the one or more processors 130 according to instructions 128. While the claimed subject matter is not limited to any particular data structure, data can be stored in a computing device register, in a relational database, as a table with multiple different fields and records, an XML document, or a flat file. Data can also be formatted in any computing device-readable format.

[0026] Instruction 128 can be any set of instructions (such as machine code) that is directly executed by the one or more processors 130 or indirectly executed by the one or more processors 130 (such as scripts). For example, instructions can be stored as computing device code on a computing device readable medium. In that respect, the terms "instruction" and "program" can be used interchangeably herein. Instructions can be stored in object code format for direct processor processing, or in any other computing device language that includes scripts or collections of independent source code modules that are interpreted on demand or pre-compiled. The function, methods, and routines of instructions are explained in more detail below.

[0027] One or more processors 130 may be microprocessors, logic circuits (e.g., logic gates, flip-flops, etc.) hardwired into the device 110 itself, or may be dedicated application-specific integrated circuits (ASICs). It should be understood that one or more processors 130 are not limited to hardwired logic circuits and may include any commercially available processing unit or any hardware-based processor, such as a field-programmable gate array (FPGA). In some examples, one or more processors 130 may include state machines.

[0028] When instruction 128 is executed by one or more processors 130, the one or more processors may detect an error condition and activate a power control feature in response. For example, the power control feature may include transmitting a square wave signal to a first transistor via a control line, causing the capacitor coupled to the first transistor to drain, which in turn turns on a second transistor, and subsequently prevents a third transistor from turning on, thereby blocking the reception of the input voltage.

[0029] Figure 2 An example block diagram illustrating an electronic device 160 is provided, wherein a power control circuit 200 is located between a power input section, such as a charging cable input port, and other device components 261. As described below, a gating component, such as a transistor, between the power supply 210 and the device component 261 is capable of stopping current flow when the input voltage is too high, thereby preventing damage to the device component 261.

[0030] Circuit 200 includes a control line VBUS_C coupled to a microcontroller unit (MCU) 230. As shown, the control line VBUS_C is coupled to a first transistor Q101, and a capacitor C102 is coupled in parallel across the junction of the first transistor Q101. The capacitor C102 is further coupled to a second transistor Q2 between the input power line V_BUS and the gate of a third transistor Q1. The third transistor Q1, coupled to the second transistor Q2 and the device component 261, interrupts the input power line V_BUS and outputs a modified input power line V_BUS_IN.

[0031] During normal operation, the input V_BUS line is at a normal voltage of 5V. Zener diode D4 is not conducting, so the base of Q2 is biased to the V_BUS level through R6 and R7, and Q2 is off. The VBUS_C line is at a stable level, and no current can flow through the DC blocking capacitor C101. The gate of Q101 is pulled to ground by R101, and Q101 is off. Q1 will not draw current from the base of Q2. Q2 remains off, and then the gate of Q1 is pulled to ground by R8, Q1 turns on, and supplies current to device 261.

[0032] The MCU can monitor and detect errors. For example, the MCU can detect conditions that will require powering down the circuit. The MCU is monitoring the voltages on V_BUS, V_BUS_IN, and several other nodes, and can generate events that shut down the power path.

[0033] When an error is detected, the MCU 230 sends a square wave to the control line VBUS_C, for example, by sending an AC signal that repeatedly toggles on and off. In response, Q101 toggles on at a positive edge and discharges capacitor C102, while keeping the node low. The second transistor Q2 turns on, and the third transistor Q1 turns off. This AC control feature prevents errors in the MCU from occurring under corner conditions such as during boot or when power is low. If C101 is not present, a high level on the control line VBUS_C could turn on the first transistor Q101, keep the third transistor Q1 off, and cut off power to the system, thus preventing the circuit from booting.

[0034] If a high voltage is received from power supply 210, the high voltage will pass through resistor R6 and Zener diode D4. If the voltage is greater than a predetermined threshold, such as greater than 6.5V, resistor R6 will have a voltage drop greater than a second threshold, such as greater than 0.7V, which will cause the second transistor Q2 to turn on, which in turn causes the third transistor Q1 to turn off. As a result, no power reaches device component 261 through the third transistor Q1 or along the modified input power line V_BUS_IN.

[0035] The predetermined threshold voltage that triggers the second transistor Q2 to turn on can be determined based on, for example, an acceptable voltage limit of device component 261. This predetermined threshold voltage can be used to determine the value of resistor R6. For example, if the predetermined threshold voltage is 6.5V, the value of resistor R6 could be 10k ohms. However, if the predetermined threshold voltage is set higher or lower than 6.5V, the value of resistor R6 can be adjusted accordingly so that the resulting voltage drop will cause the second transistor Q2 to turn on.

[0036] The MCU 230 can be an MCU or any other type of processing unit, such as a system-on-a-chip (SOC), ASIC, or FPGA / CPLD.

[0037] like Figure 2 The first transistor Q101 shown in the example is a metal-oxide-semiconductor field-effect transistor (MOSFET). In other examples, the first transistor Q101 can be a field-effect transistor (FET), a bipolar junction transistor (BJT), or any other type of transistor. Similarly, although the second transistor Q2 is shown as a BJT and the third transistor Q1 is shown as a MOSFET, other types of transistors can be used in other examples.

[0038] Example Method

[0039] In addition to the operations described in conjunction with the system above, various operations will now be described in conjunction with example methods. It should be understood that the following operations do not necessarily have to be performed in the exact order described below. Rather, various operations can be processed in different orders or simultaneously, and operations can be added or omitted.

[0040] Figure 3 A flowchart illustrating an example method 300 for operating an electronic device with AC power control features is provided.

[0041] In box 310, it is determined whether an error has been detected. For example, the MCU can determine whether an error condition exists. Examples of such error conditions include any situation that would require powering down the circuit.

[0042] If a fault is detected in block 310, the MCU sends a square wave to the first transistor via the control line (block 320). The square wave discharges the capacitor coupled across the transistor (block 330). As a result of the discharged capacitor, the second transistor coupled to the capacitor is turned on (block 340). This causes the third transistor coupled to the second transistor and the input power line to turn off (block 350). When the third transistor is turned off, it interrupts the flow of power across the input power line, thereby preventing power from reaching other components of the electronic device.

[0043] If no fault is detected at box 310, the electronic device operates in its default operating state. In this default operating state, the control line from the MCU remains stable (box 325). Thus, the first transistor remains off (box 335), the second transistor remains off, and the third transistor remains on, allowing the voltage received from the input to be passed to other components of the electronic device via the third transistor (box 345).

[0044] Figure 4 A flowchart illustrating an example method 400 for operating an electronic device is provided. This method involves handling an excessively high voltage received at an input, where the excessively high voltage exceeds the permissible limits of the circuitry in the electronic device.

[0045] In block 410, a voltage is received at the input. If the voltage exceeds a first threshold (block 420), the resistor coupled to the input will have a voltage drop exceeding a second threshold (block 430). For example, the resistor can be selected to have an ohmic value based on the first threshold, such that when the received voltage exceeds the first threshold, the resulting voltage drop will exceed the second threshold.

[0046] In block 440, the second transistor, coupled to the resistor, is turned on because the voltage drop exceeds the second threshold. In block 450, the turning on of the second transistor causes the third transistor to turn off. When the third transistor interrupts the power line, the first and second junctions of the third transistor are coupled to the power line between the power input and other circuits, and turning off the third transistor prevents other circuits from receiving voltage.

[0047] If the voltage in box 420 does not exceed the threshold, the electronic device operates in the default mode, where the third transistor outputs the voltage it receives from the input (box 425).

[0048] The aforementioned systems and methods are advantageous because they provide mechanisms for protecting wearable devices from high-voltage inputs that could potentially damage components within the device. This protection allows for operation without pin trapping or the device entering a shutdown state.

[0049] While some of the examples described above pertain to delivering a reset to an accessory such as a pair of earpieces, it should be understood that other examples of systems and methods may include any of a number of other electronic devices.

[0050] Unless otherwise stated, the foregoing alternative examples are not mutually exclusive, but can be implemented in various combinations to achieve unique advantages. Because these and other variations and combinations of the above features can be utilized without departing from the subject matter defined by the claims, the foregoing description of the embodiments should be understood in an illustrative rather than restrictive manner. Furthermore, the provision of examples described herein and phrases such as “such as,” “comprising,” etc., should not be construed as limiting the subject matter of the claims to specific examples; rather, these examples are intended to illustrate only one of many possible embodiments. Additionally, the same reference numerals in different figures may identify the same or similar elements.

Claims

1. A voltage protection circuit for electronic devices, comprising: Control lines coupled to the first transistor; Input power line; A power interruption transistor, which is coupled to the input power line and electrically coupled to the first transistor; Specifically, the reception of a square wave signal at the first transistor via the control line causes the power interruption transistor to turn off, thereby interrupting the flow of power on the input power line. The voltage protection circuit further includes: A capacitor coupled across the junction point of the first transistor, wherein reception of the square wave signal at the first transistor causes the capacitor to drain completely; and A second transistor is coupled between the capacitor and the power interruption transistor, wherein the second transistor is turned on when the capacitor is drained.

2. The voltage protection circuit according to claim 1, wherein, When the second transistor is turned on, the power interruption transistor is turned off.

3. The voltage protection circuit of claim 1, further comprising a resistor coupled between the input power line and the second transistor, the resistor having an ohmic value based on the voltage tolerance limit of the electronic device, wherein, The reception of a voltage exceeding a threshold triggers the activation of the second transistor.

4. The voltage protection circuit according to claim 1, wherein, The control line is coupled to the control unit, and the square wave signal is received from the control unit in response to an error detection.

5. The voltage protection circuit according to claim 1, wherein, The first transistor is a MOSFET.

6. An electronic device, comprising: Input port; Electronic components; as well as A voltage protection circuit, located between the input port and the electronic component, comprises: Control lines coupled to the first transistor; Input power line; A power interruption transistor, the power interruption transistor being coupled across the input power line and electrically coupled to the first transistor; Specifically, the reception of a square wave signal at the first transistor via the control line causes the power interruption transistor to turn off, thereby interrupting the flow of power on the input power line. The voltage protection circuit further includes: A capacitor across the junction of the first transistor, wherein receiving the square wave signal at the first transistor causes the capacitor to drain completely; and A second transistor is coupled between the capacitor and the power interruption transistor, wherein the second transistor is turned on when the capacitor is drained.

7. The electronic device according to claim 6, wherein, When the second transistor is turned on, the power interruption transistor is turned off.

8. The electronic device according to claim 6, wherein, The voltage protection circuit further includes a resistor coupled between the input power line and the second transistor, the resistor having an ohmic value based on the voltage tolerance limit of the electronic device, wherein receiving a voltage exceeding the threshold triggers activation of the second transistor.

9. The electronic device according to claim 6, wherein, The control line is coupled to the control unit, and the square wave signal is received from the control unit in response to an error detection.

10. The electronic device according to claim 6, wherein, The electronic device is a wearable electronic device.

11. A method of operating an electronic device, comprising: Voltage is received at the power lines of the electronic device, which are coupled between the input section and the circuit of the electronic device; Detect when an error condition exists at the control unit; In response to the detection of the error condition, a square wave signal is transmitted to the first transistor via a control line. This square wave signal causes the power interruption transistor to turn off, preventing the circuitry of the electronic device from receiving the voltage. The transmission of the square wave signal causes the capacitor coupled across the first transistor to discharge; and The capacitor is discharged to activate the second transistor, and the activation of the second transistor causes the power interruption transistor to turn off.

12. The method according to claim 11, wherein, When the control unit does not detect the error condition, the control line remains stable.

13. The method of claim 11, further comprising activating a second transistor when the received voltage exceeds a predetermined threshold.

14. The method of claim 13, further comprising turning off the second transistor when the received voltage no longer exceeds the predetermined threshold.

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