An electronic system for a surgical instrument is disclosed. The electronic system comprises a main power supply circuit configured to supply electrical power to a primary circuit. A supplementary power supply circuit configured to supply electrical power to a secondary circuit. A short circuit protection circuit coupled between the main power supply circuit and the supplementary power supply circuit. The supplementary power supply circuit is configured to isolate itself from the main power supply circuit when the supplementary power supply circuit detects a short circuit condition at the secondary circuit. The supplementary power supply circuit is configured to rejoin the main power supply circuit and supply power to the secondary circuit, when the short circuit condition is remedied.

An electronic system for a surgical instrument is disclosed. The electronic system comprises a main power supply circuit configured to supply electrical power to a primary circuit. A supplementary power supply circuit configured to supply electrical power to a secondary circuit. A short circuit protection circuit coupled between the main power supply circuit and the supplementary power supply circuit. The supplementary power supply circuit is configured to isolate itself from the main power supply circuit when the supplementary power supply circuit detects a short circuit condition at the secondary circuit. The supplementary power supply circuit is configured to rejoin the main power supply circuit and supply power to the secondary circuit, when the short circuit condition is remedied.

Systems and methods for gate driver with field-adjustable undervoltage lockout (UVLO) are disclosed. A gate driver system comprises a control circuit and a driver circuit. The driver circuit incorporates a field-adjustable UVLO, a control logic, and an inverter. The level of the field-adjustable UVLO is adjustable by an external circuit, which can be a resistor based voltage divider. By setting the UVLO level externally adjustable and by moving a reference ground to the external voltage divider, the gate driver system is able to implement gate control for various load without needing extra ground pin.

A circuit for mitigating electric shock including an external impedance detection circuit and a test and holdoff circuit. The external impedance detection circuit detects a presence of an external impedance, such as by detecting a relative change in voltage from a startup condition and a test condition. The test and holdoff circuit inhibits operation of a power converter which delivers power to be consumed by a load. The startup condition is defined by mains power applied to the circuit with negligible power consumed by a load. The test condition is defined by non-zero power delivered to the load. According to another aspect, the external impedance detection circuit measures an input voltage using a high input power which is greater than a shock hazard threshold at a duration less than a threshold time duration and determines the presence of the external impedance based on low pass filters having different time constants.

A current monitor circuit includes a sense resistor coupled to a direct current (DC) power supply to sense a current signal, an operational amplifier (op-amp) coupled to the sense resistor to sense a voltage developed across the sense resistor, and a low-pass filter coupled to the op-amp and an analog-to-digital converter (ADC). The low-pass filter reduces aliasing due to out-of-band signal content. The current monitor circuit is coupled to the ADC to provide real-time measurements of power supply load current as input to an active power management (APM) firmware.

An electronic device having a plurality of external interfaces and capable of supplying a current to external devices connected via the external interfaces, respectively includes power supply control units corresponding to the respective external interfaces and a control unit having respective terminals for outputting a power supply control signal to the power supply control units. The control unit is configured to switch output of the power supply control signal for the power supply control unit corresponding to the selected external interface and control the power supply control signal for the power supply control units corresponding to the selected external interface to be switched off in a case where a state of the common overcurrent detection signal is changed in response to the switching of the output of the power supply control signal.

A protection circuit for protecting an energy storage device includes a first circuit region between a first terminal of the energy storage device and a first connector node, a second circuit region between a second terminal of the energy storage device and a second connector node, a latching circuit to electrically couple the first connector node to the first terminal of the energy storage device when the latching circuit is in a closed configuration, and a contactor circuit electrically coupled to an operational switch of the latching circuit, the contactor circuit comprising a capacitor to store charge and a microcontroller to monitor an electrical property of the energy storage device to determine if a short circuit occurs and, if a short circuit does occur, cause the capacitor to discharge to the operational switch of the latching circuit to cause the latching circuit to transition to the open configuration.

An under-voltage lockout (UVLO) circuit configured for indicating that an electronic device may be enabled and disabled based on threshold levels of a power supply voltage. The UVLO circuit has a non-differential comparator configured to have a fixed threshold voltage. A voltage divider having a first terminal connected to the power supply voltage and configured to adapt a compare signal applied to the non-differential comparator to be proportional the power supply voltage such that a desired threshold voltage for the power supply voltage causes the non-differential comparator to change its output state. The UVLO circuit has a hysteresis controller configured for adjusting the compare voltage such that the power supply voltage has at least two threshold voltages to cause the non-differential comparator to change states. The non-differential comparator comprises a flipped gate transistor with a gate-to-source threshold greater than a normally gated transistor.

Example implementations relate to determining a failure event of a power supply. In some examples, an apparatus may comprise logic circuitry coupled to a signal line, the logic circuitry to receive a monitor signal via the signal line, where the monitor signal corresponds to an internal voltage of a power supply that is consumed wholly by the power supply, compare the monitor signal to a reference signal, and determine, based on the comparison, whether a failure event has occurred in the power supply.

A power supply device includes a voltage dividing circuit, a first transformer, a comparator, a second transformer, and an output stage circuit. The voltage dividing circuit generates a reference voltage according to an input voltage. The first transformer generates a transformation voltage and a feedback voltage according to the input voltage. The comparator compares the feedback voltage with the reference voltage to generate a comparison voltage. The second transformer generates a control voltage according to the comparison voltage. The output stage circuit selectively generates an output voltage according to the transformation voltage and the control voltage. If the RMS (Root-Mean-Square) value of the input voltage is higher than or equal to a threshold voltage, the output stage circuit will continuously output the output voltage. If the RMS value of the input voltage is lower than the threshold voltage, the output stage circuit will stop outputting the output voltage.