1073 results about "Pull-up resistor" patented technology

An interface detecting circuit and interface detecting method are provided, whereby operations can be carried out depending on peripheral devices connected to USB terminals, and whereby the system can be simplified and software load can be reduced. A pull-down resistor is connected to an ID terminal of a Mini-A receptacle of a peripheral device, the voltage generated by the pull-down resistor, which is pulled down by the ID terminal of the Mini-A receptacle of the peripheral device, and a pull-up resistor, which is pulled up by the ID terminal of a Mini-B receptacle of a device, is detected in an analog fashion, using a detecting section comprised of comparators, and, via a logic section, a logic output is subjected to noise cancellation in a filter section and is memorized in a register section. The operations of other devices are determined according to the states memorized in the register section.

A CPAP device wherein humidification detection and/or control is performed by a microprocessor of the CPAP device without requiring a separate humidification control chip. The microprocessor may also control the flow generator motor and the flow generator display. Further, the microprocessor may include code to prevent ‘brown-out’, and/or to detect the availability (connection and/or operability) of the humidifier. Humidifier detection may be carried out using power consumption or temperature sensor signal analysis, e.g., facilitated by use of a pull-up resistor.

A fail-safe circuit for a differential receiver can tolerate high common-mode voltages. An output from a differential amplifier that receives a V+ and a V- differential signal can be blocked by a NOR gate when the fail-safe condition is detected, such as when the V+, V- lines are open. Pullup resistors pull V+, V- to Vcc when an open failure occurs. A pair of comparators receive a reference voltage on the non-inverting input. Once comparator outputs a high when the V+ line is above the reference voltage, and the other comparator outputs a high when the V- line is above the reference voltage. When both V+ and V- are above the reference voltage, the NOR gate blocks the output from the differential amplifier, providing a fail-safe. Since the reference voltage is very close to Vcc, a high common-mode bias can exist on V+, V- without falsely activating the fail-safe circuit.

The invention discloses a USB cable, a USB interface and an adapter. A first identification pin used for identifying the cable as the conventional first-type-USB-interface-to-second-type-USB-interfacecable is additionally arranged on the first type USB interface to support the demand of identifying the first-type-USB-interface-to-second-type-USB-interface. A switch module and a first communication pin are additionally arranged to control connection and disconnection between a first pull-up resistor and a communication signal line and connection and disconnection between the first communication pin and a second communication pin so as to realize compatibility of the PD communication protocol and the conventional first-type-USB-interface-to-second-type-USB-interface.

A power-on reset circuit for generating a reset signal for an associated IC device includes a pull-up resistor connected between a supply voltage and a tracking node, a pull-down transistor connected between the tracking node and ground potential, and a voltage divider circuit connected between the supply voltage and ground potential. The voltage divider circuit has a first ratioed voltage node coupled to the gate of the pull-down transistor. For some embodiments, the voltage divider circuit includes a first resistor connected between the voltage supply and the first ratioed voltage node, a second resistor connected between the first ratioed voltage node and a second ratioed voltage node, a third resistor connected between the second ratioed voltage node and ground potential, and a shunt transistor connected between the second ratioed voltage node and ground potential has a gate responsive to the reset signal.

A fail-safe circuit for a differential receiver can tolerate noise. A latch is enabled when both differential inputs V+, V- rise above a reference voltage that is close to Vcc. The latch, once enabled, is set by an offset amplifier, signaling the fail-safe condition. The offset amplifier sets the latch when V+ is above or equal to V-. The differential amplifier has a small offset voltage to allow the latch to remain set when V+ and V- are equal in voltage. An output from a differential amplifier receiving V+ and V- can be blocked by a gate when the fail-safe condition is latched. Pullup resistors pull V+, V- to Vcc when an open failure occurs. The latch remains set when common-mode noise occurs on V+, V-, preventing noise from prematurely disabling the fail-safe condition. Such noise coupled into a broken cable is usually common-mode.

A switching power supply device that includes a feedback terminal to which a feedback signal according to a load state is input, and a comparator which compares a terminal voltage of the feedback terminal with a reference voltage and determines whether the load state is a normal load state or a light load state. The switching power supply device also includes pull-up resistors which are connected to the feedback terminal, a switch element which switches resistance values of the pull-up resistors according to the change of the load state, and a switch element which switches the resistance values of the pull-up resistors according to whether the input voltage is high or low.

Presence of a module, such as a DIMM, in an information handling system is detected by selectively altering the function of socket pins at opposing ends of the module socket for use in detection of module pins in contact with the socket pins. For example, ground pins at opposing ends of the socket are selectively interfaced with a detection circuit that applies a voltage through a pull up resistor to generate a logic high if the ground pin is not connected to a module ground pin and a logic low if the ground pin is connected to a module ground pin. Presence detection at opposing ends of the module identifies partially inserted modules where one end indicates a ground pin interface while the opposing end does not.

The present invention relates to a device connection state recognizing method capable of recognizing a connection state of devices without addition of signal lines dedicated to detection. Thus, in the method according to this invention, a portion of or all of a plurality of data signal lines are connected through pull-up resistors to a high electric potential or connected through pull-down resistors to a low electric potential in accordance with the connection state of the devices, and a processing unit reads, as structure information data, a high electric potential state/low electric potential state generated by the pull-up resistor/pull-down resistor in the portion of or all the plurality of data signal lines to recognize the connection state of the devices on the basis of the read structure information data. This invention is applicable to a various types of processing units which are to be connected through a common data bus to a plurality of devices.

A fail-safe circuit for a pair of differential input lines detects when one or both lines are open. Each line has a pull-up of a switched p-channel transistor in series with a resistor or another p-channel transistor that has its effective resistance controlled by a gate bias. The gate of the switched p-channel transistor is driven to ground when power is applied to the gate of a grounding n-channel transistor. When power is off, a p-channel connecting transistor charges the gate node from the differential input line when a positive voltage is applied to the input line, such as during a leakage test. Charging the gate node prevents the switched p-channel transistor from turning on, blocking a leakage current path through the pull-up. An N-well bias circuit can be added, which connects the N-well under p-channel transistors to power or the gate node or the input line.

A variable low voltage signal translator uses a driver for outputting a low voltage signal translation. A control circuit is coupled to the driver for enabling and disabling the driver wherein the control circuit has an input coupled to the signal to be translated. One terminal of the pull-up resistor is coupled to an output of the driver. A second terminal of the pull-up resistor is coupled to a voltage supply which provides the low voltage level of the variable low voltage signal translator.

A method for selecting an internal circuit according to a USB interface status includes: connecting a first pin of a USB interface of a terminal to a power supply through a pull-up resistor, where the first pin is a D− or D+ pin; when detecting that an external USB device is inserted into the USB interface, detecting whether the level status of the first pin is high or low; if the level status is low, connecting the D− and D+ pins to corresponding pins of a USB data communication module of the terminal and controlling charging of the terminal according to a first policy; if the level status is high, determining whether the level statuses of the D− and D+ pins are consistent, and if consistent, controlling charging of the terminal according to a second policy; if inconsistent, controlling charging of the terminal according to a third policy.

A two-wire serial (TWS) bus allows bus mastering by any device on the bus utilizing pull-ups. The bus is actively driven low, but typically pulled high by pull-up resistors for each device on the bus. When some of the devices on such a bus have backup power, draining of backup power whenever primary power is lost is avoided by isolating the devices with backup power from the devices without backup power on the TWS bus.

The present invention relates to an LED lamp and a drive circuit thereof, wherein, the drive circuit comprises a rectifying unit, a voltage reduction unit, constant-current drive unit and an emergency unit. In the emergency unit, the base electrode of a triode is connected with the output of the voltage reduction unit through a first divider resistance while the emitter of the triode is grounded;a second divider resistance is connected between the base electrode and the emitter of the triode; the collector electrode of the triode is connected with the grid electrode of an MOS tube; the source electrode of the MOS tube is connected with the output of an emergency power supply while the drain electrode is connected with the power input of the constant-current drive unit; a pull-up resistoris connected between the grid electrode and the source electrode of the MOS tube; and the positive electrode of a blocking diode is connected with the output of the voltage reduction unit while the negative electrode is connected with the power input of the constant-current drive unit. The present invention can guarantee that the constant-current drive unit can output current for driving LEDs to work and light normally even though alternate current fails.

A bus switch chip is limited to operating with a power-supply voltage of 1.8 volts relative to a 0-volt ground. Differential bus signals switched through the bus switch chip swing from 2.7 to 3.3 volts, well above the chip's specified power-supply voltage. The bus switch chip is level-shifted by applying a 1.5-volt signal as the chip's ground, and a 3.3-volt signal as its power supply, so the chip's net power supply is within the specification at 1.8 volts. High-Definition Multimedia Interface (HDMI) and Digital Visual Interface (DVI) require that the differential signals are never driven to ground. However, some non-compliant video transmitters drive differential signals to ground when disabled. External pullup resistors or internal pullup transistors in the bus switch chip are added to the bus signals from non-compliant transmitters to pull disabled signals above the 1.5-volt chip ground to prevent damage from signals below the chip's 1.5-volt ground.

The invention provides a half-duplex automatic receiving-transmitting switching circuit of an RS485, which comprises a microprocessor, an RS 485 communication chip and an RS 485 bus, wherein the data receiving pin of the microprocessor is connected with the receiver output end of the RS 485 communication chip; the data transmitting pin of the microprocessor is connected with the base of a triode through a current-limiting resistor; the collector of the triode is connected with the receiver output enabling end and a transmitter output enabling end of the RS 485 communication chip, and is connected with a power supply through a third resistor at the same time; the emitter of the triode is earthed; the transmitter input end of the RS 485 communication chip is earthed; the pin A of the RS 485 communication is connected with the power supply through a pull-up resistor; and the pin B of the RS 485 communication chip is earthed through a pull-down resistor. The half-duplex automatic receiving-transmitting switching circuit of the RS485 provided by the invention can automatically switch the working states of transmitting and receiving.

An apparatus for detecting a type of fan and controlling the fan, the fan providing during operation a tachometer signal indicating a speed of the fan, the apparatus includes: a direct current (DC) generator for coupling to the fan and configured to provide a first voltage to the fan; a resistor for providing, while the DC generator provides the first voltage, a sensed voltage relating to the type of the fan, wherein the resistor is connected to a reference voltage and for coupling to a pulse-width modulation (PWM) control terminal of the fan; an input judgment component coupled to the resistor to receive the sensed voltage, the input judgment component being configured to determine whether the fan is a 4-wire PWM fan with an internal pull-up resistor based on the sensed voltage and to provide a judgment signal indicating the determination; a PWM generator coupled to the input judgment component to receive the judgment signal, the PWM generator being configured to provide to the fan a PWM control signal to control the fan if the judgment signal indicates that the fan is the 4-wire PWM fan with an internal pull-up resistor; and a tachometer coupled to the DC generator and the PWM generator, the tachometer being configured to receive the tachometer signal to detect a change in the speed of the fan.

A bus switch circuit includes a switch element having two terminals whose electrical connection is controlled when a control signal is input into a control terminal. The bus switch circuit further includes a first pull-up resistor and first switch circuit, a second pull-up resistor and second switch circuit. The control signal controls the electrical connections of the first and second switch circuits.

An information handling system (IHS) includes a host computer with a downstream facing host computer serial communication bus port and a serial communication bus host controller, wherein the controller is configured to detect a serial communication bus device connected to the downstream facing host computer serial communication bus port, wherein the serial communication bus device has a pull-up resistor. The IHS further includes a circuit disposed between the serial communication bus host controller and the downstream facing host computer serial communication bus port, the circuit configured to disable the downstream facing host computer serial communication bus port and comprising at least one tri-state buffer.

The invention relates to a three-phase power input open-phase detection circuit, which comprises a first current limiting resistor, a second current limiting resistor a third current limiting resistor, a pull-up resistor, a first diode, a second diode, a third diode, a fourth diode, a fifth diode, a first filter capacitor, a first voltage stabilizing diode, a fourth current limiting resistor, an optical coupler, a triode, a fifth current limiting resistor and a second filter capacitor, wherein the first filter capacitor and the first voltage stabilizing diode are connected to the cathode of the first diode and the anode of the second diode; one end of the fourth current limiting resistor is connected to the cathode of the first diode; the output end collector of the optical coupler is connected to the pull-up resistor, and the output end emitter of the optical coupler is connected to signal ground; the collector of the triode is connected with the input end cathode of the optical coupler, the base of the triode is connected to the fifth current limiting resistor, and the emitter of the triode is connected with the anode of the second diode; one end of the fifth current limiting resistor is connected to the cathode of the fifth diode; and the second filter capacitor is connected to the cathode of the fifth diode and the anode of the second diode. The circuit overcomes the defects of high cost, complex software processing and low reliability in the conventional circuit.

When a regular reflection light receiving unit is receiving a reflected light in a non-image area where the test patches are not formed, a clamp switch is closed. Then, a first reference voltage generated by a pull-up resistor and a zener diode is corresponded to an electric potential of a terminal of a capacitor on the side of an A/D converter. The capacitor is charged by the difference in electric potential between the first reference voltage and an output voltage from the regular reflection light receiving unit. Next, the clamp switch is opened. After the regular reflection light receiving unit receives the reflected light from an image area where the test patches are formed with this state of things, the output voltage from the regular reflection light receiving unit is changed. The difference in density between the image area and the non-image area can be quantified by the A/D converter.

An impedance matching circuit of a semiconductor memory device performs a ZQ calibration with initial values that reflect an offset error according to variations in a manufacturing process. The impedance matching circuit includes a first pull-down resistance unit, a first pull-up resistance unit, and a code generation unit. The first pull-down resistance unit supplies a ground voltage to a first node, thereby determining an initial pull-down code. The first pull-up resistance unit supplies a supply voltage to the first node, thereby determining an initial pull-up code or a voltage level on the first node. The code generation unit generates pull-down and pull-up calibration codes using the initial pull-down and pull-up codes as respective initial values.

The invention provides a Bluetooth earphone with multiplexing of an USB (Universal Serial Bus) interface. The Bluetooth earphone comprises the USB interface, a charging management circuit, a microphone circuit, an pull-up resistor, a logical judgment circuit and an analog selecting switch, wherein the microphone circuit is electrically connected with a fourth pin and capable of inputting audio signals, and can serve as a divider resistor when external equipment is audio equipment; the fourth pin is connected to a bias power supply of a microphone through the pull-up resistor and synchronously and electrically connected with the input end of the logical judgment circuit for providing a voltage value belonging to the type of the external equipment to the logical judgment circuit; the control output end of the logical judgment circuit is electrically connected with the control input end of an analog switch, and the logical judgment circuit is used for controlling the selection output of the analog switch according to the received voltage value belonging to the type of the external equipment; and the analog selecting switch is used for selecting data transmission or audio output under the control of the logical judgment circuit. The Bluetooth earphone can realize the audio input/output function and the charging function by virtue of the audio interface, so that the quantity of outside interfaces is reduced, the product is nicer, the interface devices are saved, and the cost is reduced.