Abstract: In a circuit to convert a first logic signal having a first range to a second logic signal having a second range, a first transistor selectively couples an output node to a first reference voltage when the output node is to be in a first state. A second transistor selectively discharges the output node toward a second reference voltage via a resistor when the output node is to transition from the first state to a second state, the second state being a logical complement of the first state. A source-follower circuit has a source follower output coupled to the output node and has a dynamic current source, the dynamic current source having a control input coupled to the resistor. A third transistor selectively couples the source follower output to the dynamic current source when the output node is to be in the second state.

Abstract: Methods, devices, and systems are disclosed, including those for a buffer having pre-driver circuitry configured to provide voltages to thin-gate dielectric transistors. One such buffer may comprise a primary pull-up pre-driver operably coupled to a primary pull-up transistor, a secondary pull-up pre-driver operably coupled to a secondary pull-up transistor, a primary pull-down pre-driver operably coupled to a primary pull-down transistor, and a secondary pull-down pre-driver operably coupled to a secondary pull-down transistor. Each of the primary pull-up pre-driver, the secondary pull-up pre-driver, primary pull-down pre-driver, and the secondary pull-down pre-driver are configured to provide a voltage to a gate of a transistor operably coupled thereto at a voltage level so as to sustain gate dielectric integrity of the transistor.

Abstract: A slew-rate adjusting apparatus for use in a semiconductor memory device includes: a slew-rate modulation signal generator for generating a slew-rate modulation signal according to the number of control codes having a first logic level among a plurality of control codes, which are programmable at an exterior; and a pre-driver for adjusting a slew rate of a data signal by changing the number of switching elements turned on in response to the slew-rate modulation signal.

Abstract: In one embodiment, an integrated circuit has configurable application circuitry that operates at any one of multiple available power supply voltages. PT-control circuitry, operating at a PT reference voltage, generates a PT-control signal indicative of variations in process and temperature. Application-control circuitry controls the configuration of the application circuitry based on the selected power supply voltage for the application circuitry and the PT-control signal, where the selected power supply voltage is independent of the PT reference voltage.

Abstract: A driver includes a plurality of first PMOS transistors, a first resistor, a amplifier, a second PMOS transistor and a second resistor. The amplifier herein receives a reference voltage and outputs a regulating voltage. The above-mentioned reference voltage is produced in accordance with a band-gap reference voltage. Since the band-gap reference voltage is unlikely affected by a process variation, thus, the present invention is capable of providing an output current robust from process characteristic and the output current is more reliable to indicate a data signal.

Abstract: A self-adaptive output buffer for an output terminal of an electronic circuit suitable to be connected to a load is proposed. The self-adaptive output buffer includes means for sensing an indication of the capacitance of the load and means for driving the load according to the sensing, wherein the means for sensing includes capacitive means with a preset capacitance, means for charging the capacitive means to a preset voltage, means for coupling the charged capacitive means with the load, and means for measuring a measuring voltage at the capacitive means due to a charge sharing between the capacitive means and the load.

Abstract: A pull-up circuit comprises an operational amplifier which forms part of a feedback circuit, acting to bring a pull-up circuit output equal to a reference voltage input. The pull-up circuit may form part of a USB transceiver for incorporation in a USB Device. When the supply voltage of the USB Device is sufficiently high, it is used to provide the required pull-up voltage, with the feedback circuit including the operational amplifier the USB Device is not high enough to provide the required pull-up voltage. In that case, the USB bus voltage is used to generate the reference voltage which is used as an input to the feedback circuit.

Abstract: A low voltage differential signaling (LVDS) transmitter receives a data signal, a data invert signal and a plurality of logic signals. The LVDS transmitter includes a first-stage differential signaling transmitting circuit and a second-stage differential signaling transmitting circuit. The first-stage differential signaling transmitting circuit receives the data signal and the data invert signal and has a first output terminal and a second output terminal. The second-stage differential signaling transmitting circuit is controlled by the logic signals, and has a third output terminal and a fourth output terminal respectively connected to the first output terminal and the second output terminal, so as to generate a needed pre-emphasis signal. When no pre-emphasis signal needs to be generated, the second-stage differential signaling transmitting circuit is controlled to be in disabled state.

Abstract: A current drive circuit includes a differential voltage detector configured to detect a voltage level of a drive node and configured to compare the voltage level of the drive node with a voltage level of a reference voltage to generate a comparison signal, a control logic circuit configured to generate a control signal to provide a current to the drive node based on the comparison signal, and a current driver configured to provide the current to the drive node or provide the current from the drive node based on the control signal. The voltage level of the drive node rapidly reaches the voltage level of the reference voltage.

Abstract: An interface driver circuit comprises N cascaded delay cells, each including a data bit input, a delayed data bit output that communicates with the data bit input of an adjacent one of the N cascaded delay cells, and a delay time input that sets delay values between receiving data at the data bit input and generating the delayed data bit output. N predrivers receive an output enable signal that is independent of the data, receive a corresponding one of the N delayed data bit outputs and generate a predriver output signal based on the output enable signal and the corresponding one of the N delayed data bit outputs.

Abstract: Systems and methods for dynamically adjusting operation of a circuit within a semiconductor device are described herein. At least some illustrative embodiments include a system that includes a matching circuit including a first plurality of switching devices coupled to each other in parallel and not coupled in parallel to a resistive device, a driver circuit including a plurality of driver devices (the driver circuit adjusted based upon which of the switching devices are enabled), and processing logic that couples to the matching and driver circuits. The processing logic derives a binary value indicative of which of the switching devices are to be enabled, the binary value reflecting one or more process corners associated with the switching devices, and not reflecting one or more process corners associated with the resistive device. The processing logic further maps the binary value to a control value used to adjust the driver circuit.

Abstract: An input/output circuit has an output terminal, a first transistor, a second transistor, a pulse generator, and a bias circuit. The first transistor drives the output terminal based on a predetermined signal. The second transistor controls a potential of the gate of the first transistor. The pulse generator outputs a pulse with a predetermined time width when a level of the predetermined signal changes. The bias circuit generates a bias voltage for controlling the second transistor when the pulse is outputted, and impressing the bias voltage to the gate of the second transistor.

Abstract: A drive module for driving a load is disclosed. In one embodiment, the drive module includes an output terminal for connecting the load. A first control terminal is provided for applying a first control signal, according to which the circuit arrangement provides a supply voltage having a first or a second voltage level at the output terminal. A second control terminal is provided for applying a second control signal the slope of an edge in the event of a level change in the supply voltage being dependent on the second control signal.

Abstract: Embodiments for providing a plurality of bias voltages to input/output circuitry are disclosed.

Abstract: Serial data transmitter circuitry on a PLD includes a number of features that enable the transmitter to support many different communication protocols under a wide range of circuit conditions. Examples of features that the transmitter may include are (1) multiple pre-emphasis circuits of selectable strength and polarity, (2) selectable VOD, (3) selectable slew rate, (4) calibratable termination, (5) selectable common mode voltage, and (6) electrical idle mode.

Abstract: A receiver is constructed by a signal reception circuit including a first amplifier section adapted to generate a first current in response to a first input signal and a second amplifier section adapted to generate a second current in response to a second input signal, to thereby generate an amplification signal in accordance with a difference between the first and second currents, and a feedback signal generating circuit adapted to generate a feedback signal in accordance with the amplification signal. Driving abilities of the first and second amplifier sections are determined in accordance with the feedback signal.

Abstract: An analog buffer used in a source driver is provided. The analog buffer havs an input end, an output end, a transistor, first and second capacitors, first, second, third, fourth and fifth switches. The source and the drain of the transistor is coupled to the output end and receives a first voltage respectively. The first end of the first and the second capacitors are coupled to the gate of the transistor. The second end of the first and the second capacitors are coupled to the first end of the first, second and fourth switches and the first end of the third and fifth switches respectively. The second end of the first switch receives a second voltage. The second end of the second and third switches are coupled to the input end. The second end of the fourth and fifth switches are coupled to the output end.

Abstract: An output driver controls impedance using a mode register set. The output driver includes a main driving circuit that outputs and drives a main signal based on a data signal to a predetermined transmission line, an auxiliary driving circuit that outputs and drives an auxiliary signal to the transmission line, and a mode register set. The mode register set generates an impedance control signal group, a driving width control signal group and a delay control signal group. The amount of an auxiliary impedance (SIM), and the driving width and driving time point of an auxiliary signal (XSDR) can be controlled using the impedance control signal group, the driving width control signal group and the delay control signal group. Therefore, in accordance with the output driver of the present invention, the amount of output impedance (OIM), a pre-emphasis width and a pre-emphasis time point can be readily controlled, and the efficiency of the transmission of an output signal to a reception system is improved.

Abstract: An input/output circuit, operable in an input mode and an output mode, for receiving data and an enable signal, the input/output circuit including an input/output terminal; a pull-up output transistor including a gate; a first logic circuit including an output node coupled to the gate of the pull-up output transistor; a pull-down output transistor including a gate; a second logic circuit coupled to the gate of the pull-down output transistor, and the second logic circuit inactivating the pull-down output transistor in the input mode; and a gate signal generation unit configured to generate a gate signal for inactivating the pull-up output transistor in accordance with the enable signal and an input signal provided from an external device to the input/output terminal in the input mode.

Abstract: When a low level voltage is inputted to an input terminal IN, a transistor EF1 enters a blocked state, a first switch circuit SW1 enters a conduction state, and a second switch circuit SW2 enters the blocked state. Accordingly, a boosted voltage outputted from a voltage booster circuit CP is applied to a load R. When a high level voltage is inputted to the input terminal IN, the transistor EF1 enters the conduction state, the first switch circuit SW1 enters the blocked state, and the second switch circuit SW2 enters the conduction state. Accordingly, a voltage equivalent to that at the external power supply terminal VDD is applied to the load R. Therefore, although a current constantly flows through the transistor EF1 when the boosted voltage is not required, such situation does not affect a current supplied from the voltage booster circuit CP.

Abstract: Apparatus, methods, and systems include an off-chip driver having an output drive coupled in parallel with the off-chip driver to provide initial drive emphasis for a period of time. The output drive may include a first transistor and a second transistor coupled to an output of the off-chip driver to provide additional initial drive emphasis strength when both transistors are energized for an initial period of time. The time period may be set by an inverted delay circuit.

Abstract: A high voltage circuit driver includes high and low side driver cells to drive a high and a low side power MOSFET, a bootstrap circuit to energize the high side driver cell, a high voltage PMOS transistor (HVPMOS) between a voltage source and the bootstrap circuit, wherein the HVPMOS is embedded in an N-isolation layer and is integrated with the driver cells. A bootstrap control circuit, for controlling the HVPMOS, includes a high voltage level shift stage, which can also be embedded in an N-isolation layer. The circuit driver is operated by switching the high side drive signal from high to low, the low side drive signal from low to high with a first delay, and a bootstrap control signal from high to low with an additional second delay. Also, the bootstrap capacitor is first charged by switching on the HVPMOS, and then it energizes the high side driver cell.

Abstract: An on-die termination circuit is capable of increasing a resolution without enlargement of a chip or a layout size. The on-die termination circuit includes a control means, a termination resistance supply means, a code signal generating means. The control means sequentially generates a plurality of control signals in a response to a driving signal. The termination resistance supply means supplies a termination resistance in response to a coarse code signal having a plurality of bits and a fine code signal having a plurality of bits. The code signal generating means controls the fine code signal and the coarse code signal in response to the plurality of the control signals in order that the termination resistance has a level which is correspondent to an input resistance.

Abstract: A buffer for a programmable logic device has programmable current sink and source circuitry and an independently programmable common-mode voltage reference source. An amplifier, responsive to a common-mode voltage detector and the voltage reference source, forces a common-mode voltage of an output signal from the buffer to approximate the voltage from the common-mode voltage reference source.

Abstract: A method of operating an electronic device having an output driver with on die termination legs ODT, and non-ODT legs, includes the step of selectively tri-stating tuning transistors (ZQ trim devices) in the legs as a function of the operational state of the output driver. The tri-stating step is performed such that when a leg is not being utilized, the tuning transistors in the unused leg are placed in a tri-state. For example, during an ODT mode of the output driver, the tuning transistors in the non-ODT legs are tri-stated. During a READ mode of the output driver, the tuning transistors in the ODT legs are tri-stated. During a HiZ mode of the output driver, the tuning transistors in both legs are tri-stated. Tri-stating the tuning transistors in the unused output driver legs can reduce DQ pin capacitance by a total of approximately (Cgd+Cgs+Cgb).

Abstract: Systems and methods are disclosed herein to provide improved I/O techniques. For example, in accordance with an embodiment of the present invention, an integrated circuit includes a driver that receives data signals and provides an output signal based on the data signals, with the driver having a plurality of transistors with a first set of the plurality of transistors adapted to provide a first logical value as the output signal and a second set of the plurality of transistors adapted to provide a second logical value as the output signal based on the data signals. A sequencing circuit provides the data signals to the driver such that the first set of the plurality of transistors is switched on before the second set of the plurality of transistors is switched off, and the second set of the plurality of transistors is switched on before the first set of the plurality of transistors is switched off.

Abstract: A voltage buffer and the source driver thereof are disclosed. The above-mentioned voltage buffer includes an operational amplifier and an overdriving unit, wherein the operational amplifier outputs an output voltage. The overdriving unit is coupled between an input voltage and the operational amplifier for comparing the input voltage with the output voltage and outputting an overdriving voltage to the positive input terminal of the operational amplifier. Herein if the input voltage is greater than the output voltage, the overdriving voltage is greater than the input voltage; if the input voltage is less than the output voltage, the overdriving voltage is less than the input voltage; if the input voltage is equal to the output voltage, the overdriving voltage is equal to the input voltage.

Abstract: Embodiments are described for an output driver circuit capable of maintaining a substantially constant output impedance across a wide range of output voltages. The driver circuit includes a pull-up circuit and a pull-down circuit, each having two or more current paths that either source currents to or sink currents from the output node. The addition of the third current path provides additional current such that the sum of the total currents have a magnitude that changes linearly as the output voltage at the output node is being driven.

Abstract: A line driver device is provided in which an output stage can be controlled so as to provide an output current according to at least a first or a second operating mode of the line driver device, the first operating mode corresponding to a class A mode of the line driver device and the second operating mode corresponding to a class B mode of the line driver device.

Abstract: An on-die termination circuit is capable of increasing a resolution without enlargement of a chip or a layout size. The on-die termination circuit includes a control means, a termination resistance supply means, a code signal generating means. The control means sequentially generates a plurality of control signals in a response to a driving signal. The termination resistance supply means supplies a termination resistance in response to a coarse code signal having a plurality of bits and a fine code signal having a plurality of bits. The code signal generating means controls the fine code signal and the coarse code signal in response to the plurality of the control signals in order that the termination resistance has a level which is correspondent to an input resistance.

Abstract: A semiconductor memory device is capable of adjusting effective data period of data. The semiconductor memory device includes a buffering unit for buffering input data, a window adjusting unit, and a transmitting unit. The window adjusting unit is for adjusting a window of the buffered data outputted from the buffering unit in response to plural metal option. The window adjusting unit includes a first driving unit for driving an output node in response to the output signal from the buffering unit and a second driving unit for additionally driving the output node in response to the output signal from the buffering unit. Meanwhile, the transmitting unit delivers output of the window adjusting unit into a core block.

Abstract: A transmission device including: a driver unit which generates an output signal having an amplitude by a resistance division of a power-supply voltage; and an output-amplitude correction unit which generates current according to variation in the power-supply voltage, and corrects the amplitude by using the current.

Abstract: A method of operating an electronic device having an output driver with on die termination legs ODT, and non-ODT legs, includes the step of selectively tri-stating tuning transistors (ZQ trim devices) in the legs as a function of the operational state of the output driver. The tri-stating step is performed such that when a leg is not being utilized, the tuning transistors in the unused leg are placed in a tri-state. For example, during an ODT mode of the output driver, the tuning transistors in the non-ODT legs are tri-stated. During a READ mode of the output driver, the tuning transistors in the ODT legs are tri-stated. During a HiZ mode of the output driver, the tuning transistors in both legs are tri-stated. Tri-stating the tuning transistors in the unused output driver legs can reduce DQ pin capacitance by a total of approximately (Cgd+Cgs+Cgb).

Abstract: A high-speed differential receiver is used between a high voltage domain and a low voltage domain. The high-speed differential receiver includes a common mode differential amplifier coupled to a differential level shifter. The common mode differential amplifier and differential level shifter operates at the high voltage domain. The differential level shifter receives amplified differential signals from the common mode differential amplifier and provides voltage level shifted differential signals applied to a biased differential amplifier operating at the low voltage domain.

Abstract: A programmable differential signaling system includes a programmable bias generator and a plurality of input/output modules. The programmable bias generator is operably coupled to generate a first global bias signal and a second global signal based on desired signal properties of one of a plurality of differential signaling conventions. The a plurality of input/output modules is operably coupled to convert between differential signaling and single ended signaling, wherein actual signal properties of the differential signaling are regulated based on the first and second global bias signals to substantially equal the desired signal properties.

Abstract: An I/O buffer circuit including: a driver circuit containing a pull-up device in a first floating well and a pull-down device in a second floating well; a first and second biasing circuits to bias the first and second floating wells in response to voltages internal and external to the I/O buffer circuit; and a first and second tracking circuits to bias each of said pull-up and pull-down devices in response to voltages internal and external to the I/O buffer circuit in a shutdown mode.

Abstract: Provided is a pre-driver circuit having a pull-up unit for receiving a data signal, as an input, to output a logical High; a pull-down unit for receiving the data signal, as an input, to output a logical Low; and a control unit for using a control signal reflecting a process completion status to adjust a driving size of the pull-up unit and/or the pull-down unit. According to the present invention, slew of a waveform of an output data can be stably secured regardless of a process condition.

Abstract: An H-bridge drive circuit for reducing switching noises while preventing shoot-through current from flowing in the H-bridge circuit. The H-bridge drive circuit includes an H-bridge circuit for driving a load with a first power supply and a lower voltage second power supply. The H-bridge circuit includes first to fourth transistors. The first and third transistors are connected to the first power supply. The second transistor is connected between the first transistor and the second power supply, and the fourth transistor is connected between the third transistor and the second power supply. The load is connected to a node between the first and the second transistors and a node between the third and the fourth transistors. A control circuit switches the activation and inactivation of the first to fourth transistors so as to maintain at least either one of the second and fourth transistor in an activated state.

Abstract: An output driver for use in a semiconductor is capable of maintaining its slew rate constantly regardless of PVT (Process/Voltage/Temperature) variation. The output driver includes a pre-driving unit for pre-driving a data signal; a main driving unit for driving an output pad in response to the output signal of the pre-driving unit; and a slew rate modeling unit for generating a pre-driver bias signal to constantly maintain effective resistances of a pull-up path and a pull-down path of the pre-driving unit by modeling the pre-driving unit.

Abstract: A slew rate controlled circuit driver generates a binary output signal with strong direct current (DC) characteristics based on a received binary logic signal, while minimizing crowbar current. The slew rate controlled circuit driver may include a first driver with smaller transistors that open and/or close quickly to allow a generated output signal to meet required rise and fall time requirements, and may include a second driver with larger transistors that open and/or close more slowly, that allow the generated output signal to support for strong DC signal characteristics, such as support for high DC current loads without degrading the DC voltage signal levels. Further, OPEN and CLOSE states of transistors within each of the first and second drivers may be controlled to reduce, during switching between HIGH and LOW output signal states, the establishment of paths between HIGH signal sources and LOW signal sources that contribute to crowbar current.

Abstract: A slew-rate controlled driver circuit in an integrated circuit fabricated in a low voltage CMOS process, having an input node and an output node. A PMOS pull-up transistor is provided, having a source connected to one side of a power supply, having a gate, and having a drain connected to the output node. The PMOS transistor also has a parasitic capacitance between its gate and drain, having a value that may vary from one integrated circuit to the next from process variations and in response to varying circuit conditions. A current source generates a current having a level corresponding to the value of the parasitic capacitance, and to provide that current to the gate of the PMOS transistor. A level shifter receives an input signal having a voltage varying in a first range provides as output signal to the gate of the PMOS transistor shifted to a level suitable for the PMOS transistor.

Abstract: A transceiver interface for data transfer between two integrated circuits (ICs or “chips”) utilizes a current mode technique rather than conventional voltage mode differential signaling techniques. A current pulse is injected into one of two transmission wires based on a signal value to be transmitted (e.g., logic “0” or “1”) by a driver on a transmitting chip. The current pulse is received as a differential current signal at a receive block in a receiving chip. The differential signal is converted to a low swing differential voltage signal by current comparators. The differential voltage signal may be detected by an op-amp receiver which outputs the appropriate signal value.

Abstract: Apparatus and methods advantageously maintain transistors of open-drain differential pairs biased in the saturation region when “active,” rather in than the triode or linear region. The biasing techniques are effective over a broad range of process, voltage, and temperature (PVT) variations. By controlling a high voltage level used to drive the gate of a transistor of the differential pair, the biasing of the transistor in the saturation region is maintained. In one embodiment, the low voltage level used to cut off the transistor of the differential pair is also controlled. These techniques advantageously permit differential drivers to exhibit relatively large output swings, relatively high edge rates, relatively high return loss, and relatively good efficiency.

Abstract: A transistor drive circuit of a power converter is developed for operating in a wide voltage range. It includes an N-type high-side transistor, a P-type high-side transistor and an N-type low-side transistor. A voltage clamp device is connected to the gate of the N-type high-side transistor to limit the maximum output voltage. A detection circuit is coupled to detect the supply voltage of the transistor drive circuit to generate a disable signal in response to the voltage level of the supply voltage. The disable signal is coupled to disable the P-type high-side transistor once the voltage level of the supply voltage is higher than a threshold voltage.

Abstract: In one aspect, the present invention comprises an electrostatic discharge (ESD) protection circuit comprising a plurality of input circuits in which each input circuit comprises a first PMOS and a first NMOS transistor connected in series between a power supply and ground and first and second inverters connected to the gates of the first PMOS and NMOS transistors. Each inverter connected to the gate of the first NMOS transistor comprises a second NMOS transistor connected between that gate and ground and the ratio of the width of the gate of the second NMOS transistor to the width of the gate of the first NMOS transistor of each of the input circuits is substantially the same. In another aspect of the invention, a multi-fingered gate transistor is formed in a first well of one conductivity type that is surrounded by a second well of the same conductivity type from which it is separated by a shallow trench isolation and a portion of the substrate.

Abstract: An output buffer includes at least a first and a second stage, wherein each stage is formed by respective first transistors and second transistors coupled in series with each other between a first and a second voltage reference. The coupled first and second transistors have a common conduction terminal connected to an output terminal of the output buffer. An input terminal of the buffer is connected to control terminals of the transistors of the first stage through a first open loop driving circuit. A second feedback driving circuit is connected between the input terminal and the control terminals of the transistors of the second stage. The second feedback driving circuit includes a current detector operating to detect a maximum in the value of the current drawn by and supplied to the output buffer. A comparison block, having a threshold value, detects current in excess of the threshold value and processes information coming from the current detector to regulate an output impedance value of the output buffer.

Abstract: Apparatus, methods, and systems are disclosed, such as those involving a multi-die device having a common bus to indicate a state of each of a die of a multi-die device and that provides the state of all of the dice at a common output. Such a multi-die device can comprise two or more dice in a multi-die package, wherein each of said dice has a first drive parameter when indicating a first state and a second drive parameter when indicating a second state. When the first drive parameter of the two or more dice is at a value such that when one or more of said two or more dice is in the first state, said common output can indicate that all of the dice in the multi-die device are in the first state.

Abstract: A calibration circuit for matching the output impedance of a driver by calibrating adjustments to the driver is described. The calibration circuit includes a driver circuit with a plurality of calibration transistors configured to receive a plurality of adjustment signals. The calibration circuit also includes a comparator circuit, and a binary searcher. The driver provides a signal corresponding to an output impedance to the comparator circuit. The output impedance signal is compared to a target impedance, and the comparator circuit then provides logic signals to the binary searcher representing whether the output impedance is greater than the target impedance. The binary searcher then selects a type of step size and count direction, in response to the logic signals, to count the number of steps for adjusting the calibration transistors of the driver.

Abstract: Transmission of digital signals across a bus between an electronic device having a transmitter and another electronic device having a receiver with termination for both the transmitter and receiver being referenced to ground, such that the electronic device having the transmitter and the other electronic device having the receiver are able to be powered with differing decoupled voltages, such that the voltage employed by the electronic device having the transmitter is able to be lower than the voltage employed by the other electronic device having the receiver, and wherein the electronic device having the transmitter may transmit addresses and/or commands to the other device having the receiver using single-ended signaling, while both electronic devices may exchange data using differential signaling.

Abstract: A bias circuit includes multiple output legs. During a transition from a low power state to an operational state, multiple output legs are turned on to provide a bias voltage. After a suitable period, at least one of the multiple output legs is turned off.