Abstract: A biomedical signal instrumentation amplifier is especially suitable for a circuit processing biomedical signals. In a voltage instrumentation amplifier, a biomedical signal level conversion circuit is added to change an input level, reduce signal distortion and noise, and achieve the performance of low voltage, unisource, low noise, high CMRR, and high PSRR.

Abstract: A biomedical signal instrumentation amplifier is especially suitable for a circuit processing biomedical signals. In a voltage instrumentation amplifier, a biomedical signal level conversion circuit is added to change an input level, reduce signal distortion and noise, and achieve the performance of low voltage, unisource, low noise, high CMRR, and high PSRR.

Abstract: An N times frequency multiplication circuit uses duty cycle control buffers in combination with edge detectors to provide both multiplication and 50% duty cycle adjustment. Parallel branches of duty cycle control buffers are preset for respective duty cycles of 1/N, 2/N,...,N−1/N. The buffers each receive a common edge detected input signal and simultaneously output their respective duty cycle adjusted clock signals. A rising and falling edge detector generates a pulse train at double the frequency of the 1/N buffer output, while falling edge detectors generate time spaced pulse trains from the outputs of their respective 2/N,...,N−1/N buffers. These pulse trains are combined in an OR gate to provide an output pulse train at a frequency N times the input clock frequency fin. A final stage duty cycle control buffer adjusts the N times fin output signal to a 50% duty cycle.

Abstract: An output buffer is provided which receives an input signal and drives an output terminal. The output buffer has a first driver and a second driver for driving the output terminal to a voltage level corresponding to a logic value of the input signal. The second driver has a greater (current) driving capacity than the first driver. The output buffer also has control circuitry which detects a transition in the logic value of the input signal. In response, the control circuitry generates a particular pulse aligned with the input signal logic value transition having a particular constant voltage level for a predetermined time period. Furthermore, the control circuitry delays the second circuit from driving the output terminal to a complementary voltage level corresponding to the logic value to which the input signal transitions during the predetermined time period.

Abstract: In a preferred embodiment of the present invention, a bidirectional buffer connects a first device, such as a CMOS chip having a first voltage, such as VDD, to a second device having a second voltage, such as VCC, through a terminal pad. The buffer includes a first driver for driving a terminal pad up to the first voltage, wherein the first driver preferably includes a pair of in series PMOS transistors formed in an n floating well. The buffer further includes a second driver for driving the terminal pad down to a voltage VSS. Such a structure provides a simple circuit that requires only a single terminal pad, a single power supply, and is substantially free of dc leakage currents.

Abstract: A duty cycle control buffer uses an edge detector input stage to detect the transitions of an unpredictable clock signal input. The edge detector generates one shot output signals in synchronism with the clock signal. A pulse width controllable monostable multivibrator converts the one shot signals into rectangular pulses, at the same frequency as the original clock input. The rectangular pulses are inverted and then averaged, to provide a voltage input to one side of an operational amplifier. A reference voltage is supplied to the other side of the operational amplifier, such that the difference between the average voltage and the reference voltage generates an output control voltage from the operational amplifier. This control voltage provides negative feedback to a pulse width control stage within the monostable multivibrator, thereby adjusting the pulse width of the rectangular pulse output until a steady state is reached.

Abstract: A CMOS voltage regulator uses clock signals from an adaptive swing clock generator to control the output voltage of a charge pumping circuit. A divided portion of the output voltage is fed to a differential amplifier, where it is compared to a pre-set reference voltage. A negative feedback signal is generated from the differential amplifier and inputted to the adaptive swing clock generator, where it causes the clock signals to change amplitude in an inverse relationship to changes in the output voltage. When the divided portion of the output voltage equals the pre-set reference voltage, a steady-state output voltage condition is achieved.

Abstract: In a preferred embodiment of the present invention, a bidirectional buffer connects a first device, such as a CMOS chip having a first voltage, such as VCC, to a second device having a second voltage, such as VDD, through a terminal pad. The buffer includes a bootstrap capacitor to assist in driving up the terminal pad. In particular, the buffer comprises an output and an input portion. The output portion includes a first driver for driving the terminal pad up to VDD and a second driver for driving the terminal pad down to VSS. The first driver includes a pull-up PMOS transistor and a pull-up NMOS transistor connected in series and the second driver includes a pull-down NMOS transistor. Further, preferably one pair of push-pull bootstrap control transistors are connected in parallel to the gate of the pull-up NMOS transistor for quickly driving up the first driver to a voltage level based on the bootstrap capacitor having a predetermined capacitance.

Abstract: In a preferred embodiment of the present invention an output buffer includes high current drivers that avoids a short circuit current. Further, the inventive output buffer only produces a slight level of ground bounce (noise). In particular, the buffer comprises first and second drivers for driving a terminal to a voltage corresponding to a high logic value of a first output signal and a low logic value of a second output signal, respectively. Typically, the first driver includes a plurality of PMOS pull-up transistors and the second driver includes a plurality of NMOS pull-down transistors. In addition, first and second predriver circuits, connected to the first and second drivers, respectively, are included. In operation, the first predriver receives the complement (inverse) of the first output signal and a delayed output of the second predriver. The second predriver receives the complement of the second output signal and the delayed output of the first predriver.

Abstract: An output buffer is provided which receives an input signal for output onto an output terminal. The output buffer has a first driver and a second driver for driving the output terminal to a voltage corresponding to a logic value of the input signal. The second driver has a higher driving capacity than the first driver. The output buffer also has control circuitry receiving a transition in logic value of the input signal and at least one mode signal. The control circuitry responds to the transition in logic value by delaying the second driver from driving the output terminal to a complementary voltage until after the first driver begins to drive the output terminal to the complementary voltage. In so doing, the control circuitry delays the second driver by a first delay, when the mode signal(s) indicates a full speed mode. On the other hand, the control circuitry delays the second driver by a second delay, that is longer than the first delay, when the mode signal(s) indicates a low speed mode.

Abstract: A bidirectional buffer circuit is provided with a terminal, an input buffer, a steady state output driver and a strong output driver. The input buffer is for receiving an input signal from the terminal. The steady state output driver includes a weak driver for driving the terminal to a first voltage corresponding to a first particular logic value of the output signal. The weak driver has a limited driving capacity that can be out-driven by the input signal. The strong output driver is for driving the terminal to the first voltage. The strong output driver has a greater driving capacity than the weak output driver. Enable circuitry is also provided. The enable circuitry includes at least one delay circuit with a particular delay period. The enable circuitry enables the strong output driver in response to a transition of the output signal from a complement of the first logic value to the first logic value. However, the enable circuitry only enables the strong driver during the delay period of the delay element.

Abstract: A level shifter is provided with first and second steady-state drivers and transient driver circuitry. Each steady-state driver includes a low enable input, a high enable input and an output. Each steady-state driver outputs from its respective output a low voltage level signal when an enabling voltage level is received at its low enable input and a disabling voltage is received at its high enable input. Furthermore, each steady-state driver outputs from its output a first high voltage level signal, that is higher than a second high voltage level of an input signal, when a disabling voltage level is received at its low enable input and an enabling high voltage level is received at its high enabling input. The high enable input of the first steady-state driver is connected to the output of the second steady-state driver. The high enable input of the second steady-state driver is connected to the output of the first steady-state driver.

Abstract: A low power consumption oscillator circuit is provided with an oscillator. The oscillator responds to a voltage by producing an oscillating signal at its output having an amplitude that depends on the level of the voltage. Furthermore, the low power consumption oscillator circuit has a level shifter. Illustratively, according to one embodiment, the level shifter includes a pull-up driver and a pull-down driver connected in parallel between the oscillator output and an output of the level shifter. The pull-up driver is configured so as to refrain from conducting current between a biasing input of the pull-up driver and the level shifter output simultaneously with the pull-down driver when the oscillating signal exceeds a certain voltage level. The level shifter illustratively includes an intrinsic PMOS device.

Abstract: An output buffer is provided with a terminal, a first driver, a second driver and enable circuitry. The first driver is for driving the terminal to a voltage corresponding to a logic value of the output signal. The second driver is for driving the terminal to the same voltage as the first driver, when the output signal transitions in logic value. The enable circuitry responds to a transition in logic value of the output signal by, after a predetermined delay, enabling the second driver to drive the terminal. However, the enable circuitry only enables the second driver to drive the terminal for a predetermined time period.

Abstract: A level shifting inverter is provided with first and second drivers which may be level shifting inverters, which each have a low enable input, a high enable input and an output. Each driver outputs a low voltage level or a second high voltage level(that is higher than a first high voltage level of an input signal) depending on enabling and disabling voltage levels received at the high and low enable inputs of each driver. The high enable input of the first and second drivers are connected in a cross-coupled feedback configuration. The input of the first driver receives a complement of the input signal whereas the input of the second driver receives the input signal. The level shifter also has transition driver circuitry. The transition driver circuitry has an input receiving the second high voltage level, a first biasing input receiving the input signal and a second biasing input receiving the complement of the input signal.