摘要:
Level shifter circuitry, as for an operational amplifier, imposes no current load on the preceding amplifier stage associated with its level shifter function. A common-collector-amplifier first transistor has base and emitter connections to the input and output terminals of the level shifter. A second transistor of similar conductivity type and common-collector forward current gain has its base electrode connected through a first current mirror amplifier to the input terminal of the level shifter and has its emitter electrode connected through a second current mirror amplifier to the output terminal of the level shifter. The first and second current mirror amplifiers have similar current gains. The first current mirror amplifier may also be incorporated in apparatus for supplying constant current loading to the preceding amplifier stage, to this end having a source of constant current connected to its input connection.
摘要:
A push-pull amplifier having like conductivity output transistors is driven by a phase-splitter transistor amplifier. The collector load of the phase-splitter includes a diode bridge for establishing the amplifier idling current. One arm of the bridge incorporates the pull-up output transistor base-emitter junction-the current conducted therein being accurately determined by bridge parameters.
摘要:
A controller for regulating a FET to operate as a pass device including input, output and gate nodes coupled to a current path input, a current path output and the gate of the FET, respectively, a controlled low current device, and an oscillating high gain regulation amplifier. The voltage source provides a regulation voltage level relative to the input node. The low current device is coupled to the gate node and has a control input. The amplifier has a first input coupled to the output node, a second input coupled to the voltage source, and an output coupled to the control input of the controlled low current device to regulate the FET. The amplifier oscillates while regulating a voltage between the input and output nodes to the regulation voltage level. The controlled low current device presents a high impedance to the gate node to prevent oscillations from disturbing regulation.
摘要:
An integrated sample-and-hold S/H circuit includes a subthreshold conduction current compensation circuit for reducing undesired effects of subthreshold conduction current in a first field-effect transistor (FET) during the holding time. More particularly, the S/H circuit may include a substrate, a sampling capacitor formed on the substrate, and the first FET. The first FET has a first conduction terminal for receiving the input signal, a second conduction terminal connected to the sampling capacitor, and a control terminal. The control terminal is responsive to control signals for connecting the input signal to the sampling capacitor during a sampling time and for disconnecting the input signal from the sampling capacitor during a holding time. The first FET preferably further includes a body which unfortunately creates a parasitic diode connected to the sampling capacitor. A unity gain buffer amplifier may be connected to the body of the first FET during the holding time for applying a holding voltage from the sampling capacitor to the body to thereby reduce undesired effects from the parasitic diode. The subthreshold current conduction compensation circuit causes a voltage at the first conduction terminal of the first FET to be substantially equal to a voltage at the second conduction terminal of the first FET during the holding time. This may be accomplished by coupling the holding voltage from the output of the buffer amplifier to the node between two series connected FETs.
摘要:
An integrated S/H circuit includes a first field-effect transistor (FET) formed on a substrate with a sampling capacitor, and a buffer amplifier having an input connected to the sampling capacitor and an output connectable to the body of the first FET. The buffer amplifier thereby reduces undesired effects from a parasitic diode formed by the body and sampling capacitor. More particularly, the first FET preferably has a first conduction terminal for receiving the input signal, a second conduction terminal connected to the sampling capacitor, and a control terminal responsive to control signals for connecting the input signal to the sampling capacitor during a sampling time, and for disconnecting the input signal from the sampling capacitor during a holding time. The circuit may include one or more switches for connecting the body of the first FET to the output of the buffer amplifier during the holding time to thereby apply a holding voltage from the sampling capacitor to the body of the first FET. The holding voltage overcomes the voltage droop as would otherwise be caused by the parasitic diode. The switches may also connect the body of the first FET to a supply voltage during the sampling time. In addition, the buffer amplifier may have a substantially unity gain.
摘要:
A digital phase comparator for essentially eliminating the dead zone in the phase correction means of a phase locked loop. The digital phase comparator is arranged to provide respective up and down output pulses to operate respective charge pumps. The up and down output pulses at all times are greater than a predetermined time duration no matter how small the phase difference between comparator input signals. A delay means is provided in the phase comparator logic, which delay means substantially determines such predetermined time duration. The minimum pulse duration of the up and down signals is selected to be at least of a duration sufficient to operate its respective charge pump, thereby overcoming the finite turn on time of the respective charge pump, no matter how small the phase error.
摘要:
An over-voltage protection circuit prevents an anomaly, such as a short circuit in the upper-switched electronic device of a DC-DC power supply, from propagating to downstream circuitry. The over-voltage protection circuit, which includes an overvoltage sense resistor coupled between an output of the upper or high side FET and the gate of the lower FET, is operative to sense a short circuit fault condition in the circuit path through the upper FET during initial power up of the system. In response to this condition, the lower NFET device is turned on so as to provide an immediate by-pass of the overvoltage condition to ground, and thereby prevent excessive voltage from being applied by the output terminal to downstream powered circuitry.
摘要:
A multi-level current pulse generator for driving the gates of a CMOS pair implemented using a low voltage process including a multi-level pulse translator, a current amplifier circuit, and a clamp circuit. The multi-level pulse translator generates a multi-level current pulse on at least one pulse node, each current pulse having a first large current pulse with short duration followed by at least one smaller current pulse of longer duration and operative to switch the CMOS pair with reduced average power dissipation. The current amplifier circuit amplifies the current pulses provided to the gates of the CMOS pair. The clamp circuit clamps gate voltage of the CMOS pair to prevent breakdown. In a tri-level case, a first current pulse charges and discharges gate capacitance, a second current pulse stabilizes gate voltage, and a third current pulse provides a holding current level.
摘要:
An integrated circuit sample-and-hold (S/H) circuit includes an amplifier offset compensation circuit for compensating for the D.C. offset of a buffer amplifier. The amplifier offset compensation circuit may include an offset determining circuit for determining an offset voltage generated by the buffer amplifier, and an offset correction circuit for generating an offset correction signal and coupling the offset correction signal to the buffer amplifier. The S/H circuit may include a substrate, a sampling capacitor formed on the substrate, and a first field-effect transistor (FET) formed on the substrate. The first FET may have a first conduction terminal for receiving the input signal, a second conduction terminal connected to the sampling capacitor, and a control terminal responsive to control signals for connecting the input signal to the first sampling capacitor during a sampling time and for disconnecting the input signal from the first sampling capacitor during a holding time. The first FET may further include a body creating a parasitic diode-connected to the first sampling capacitor. To address this parasitic diode, the circuit includes the buffer amplifier having an input connected to the first sampling capacitor and an output connected to the body of the first FET during the holding time. The offset of the buffer amplifier is compensated.
摘要:
First and second electrical components on an integrated circuit chip are electrically connected respectively to a wire bonding pad and to a probe contacting area of a size significantly less than the bonding pad. The pad and contacting area are electrically isolated whereby both components can be separately electrically tested by test probes contacting each of the pad and the contact area. After the components have been tested, the bonding pad and the probe contact area are electrically connected together for electrically connecting the first and second components. The electrical connection is made by bonding a terminal wire to the bonding pad as well as to an extension from the contact area substantially filling a space within the bonding pad and underlying the joint formed between the terminal wire and the bonding pad.