Abstract: A motor drive system control provides global closed loop feedback to cooperatively operate system components to adaptively reduce noise and provide noise cancellation feedback. An active EMI filter reduces differential and common mode noise on an input and provides a noise level indication to a system controller. Power switches in both a power converter and power inverter are cooperatively controlled with dynamic dv/dt control to reduce switching noise according to a profile specified by the controller. The dv/dt control is provided as an analog signal to a high voltage IC and codified as a pulse width for a level shifting circuit supplying control signals to the high voltage gate drive. A noise extraction circuit and technique obtain fast noise sampling to permit noise cancellation and adaptive noise reduction.

Abstract: A motor drive system control provides global closed loop feedback to cooperatively operate system components to adaptively reduce noise and provide noise cancellation feedback. An active EMI filter reduces differential and common mode noise on an input and provides a noise level indication to a system controller. Power switches in both a power converter and power inverter are cooperatively controlled with dynamic dv/dt control to reduce switching noise according to a profile specified by the controller. The dv/dt control is provided as an analog signal to a high voltage IC and codified as a pulse width for a level shifting circuit supplying control signals to the high voltage gate drive. A noise extraction circuit and technique obtain fast noise sampling to permit noise cancellation and adaptive noise reduction.

Abstract: A dead-time generator for incorporation in an integrated circuit wherein the integrated circuit includes a high side and low side gate driver and wherein the high side and low side gate driver drive output switches such that a dead-time is provided between on times of the output switches, the dead-time generator comprising a circuit internal to the integrated circuit having an external terminal at which a dead-time setting component is connected, and wherein the dead-time generator comprises a circuit for providing a discrete dead-time for a range of dead-time setting values at the dead-time setting terminal and wherein, for a plurality of ranges of dead-time setting values at the dead-time setting terminal, the dead-time generator generates an associated plurality of discrete dead-times.

Abstract: An integrated high-voltage linear amplifier IC with reduced power dissipation, faster operation, and small die size, comprising a low side well and a floating high side well; an error amplifier for receiving a noise signal; a level shifting circuit in the low side well for outputting a current mode error signal based on the noise signal to the high side well in differential current mode for noise reduction; and a drive circuit in the high side well. A voltage/current converter receives a voltage mode error signal based on the noise signal and supplies the current input signal. Current mirror circuitry and the drive circuit in the high side well outputs a sum current derived from the current mode error signal for driving external power devices.

Abstract: A control terminal driver circuit for a switching amplifier including a driver for each of a pair of output power transistors responsive to a PWM information signal. The circuit operates in response to an operating state signal indicating a start up condition for the amplifier to vary the amplitude of the drive pulses for the output transistors between a zero value and a maximum value for normal operation of the amplifier over a start up interval, and to reverse the process during a shut down interval. A DC offset detector is provided to detect a DC offset at amplifier output, and an error circuit responsive to an output of the DC offset detector controls the relative amplitude of the driver outputs during at least a portion of the start up interval to substantially eliminate the DC offset. Also disclosed is a switching amplifier including a control terminal driver circuit as described above.

Abstract: An apparatus and method for determining the output current in a bridge-connected switched transistor output circuit including high-side and low-side transistor switches, typically MOSFETS. The voltage at a common node between the high and low side switches is sensed, and offset in a first circuit by a fixed amount so that the voltage is positive for all positive or negative output currents of interest. The output current is actually determined in a second circuit which receives the offset voltage signal only predetermined times in relation to the on-time of the low side switch. The first circuit includes a current reference source/level shifter and a current mirror circuit formed of a plurality of transistors in a particular circuit configuration. The second circuit is coupled to an output of the first circuit by a gated NMOS transistor at the desired times to provide the current measurement signal.

Abstract: An active EMI filter senses current in a ground line as a voltage across a capacitor coupled to the ground line. The EMI filter senses common mode voltage and determines a difference between the common mode voltage and noise to provide an output to the ground line to reduce the difference.

Abstract: A control terminal driver IC for a switching circuit having series connected high and low side output transistors, an associated split power supply and a floating input, the gate drive IC, an exemplary, but non-limiting, example of which is a Class D audio amplifier. The IC includes an input circuit, a voltage to current converter connected to the input circuit, a level shifter formed in a mid well of the IC, which is operative to transfer the input signal to the low side without the need for a power supply input to the mid well, a current to voltage converter on the low side coupled to the level shifter; and an output circuit which is operative to generate control terminal drive signals for the high and low side transistors.

Abstract: A control terminal driver circuit for a switching amplifier including a driver for each of a pair of output power transistors responsive to a PWM information signal. The circuit operates in response to an operating state signal indicating a start up condition for the amplifier to vary the amplitude of the drive pulses for the output transistors between a zero value and a maximum value for normal operation of the amplifier over a start up interval, and to reverse the process during a shut down interval. A DC offset detector is provided to detect a DC offset at amplifier output, and an error circuit responsive to an output of the DC offset detector controls the relative amplitude of the driver outputs during at least a portion of the start up interval to substantially eliminate the DC offset. Also disclosed is a switching amplifier including a control terminal driver circuit as described above.

Abstract: A Class D audio amplifier including a gain stabilization feedback loop in which volume control is achieved by varying the bus voltage. Changes in the bus voltage are compensated for by complementary changes in the gain of a compensation element in feedback loop so the signal level at the output of the Class D stage can be adjusted independent of the feedback. A digital attenuator can be employed ahead of the amplifier to shift the effective gain of the amplifier output to provide additional volume control range.

Abstract: A class D amplifier is provided with a frequency characteristic compensation function. An automatic frequency characteristic compensation circuit is disposed at an input unit of a class D amplifier. The frequency characteristic of the class D amplifier is automatically measured while a load is connected, using a test signal having a predetermined frequency and signal level. An inverse characteristic is computed for compensating the frequency characteristic to the design frequency characteristic, and the inverse characteristic is set in the automatic frequency characteristic compensation circuit.

Abstract: Low pass filters at the output stage of a D-class amplifier, in which a high channel separation between adjacent signal amplifying channels, a small size, implementation at a high density can be attained. Induced electromotive forces by a leakage magnetic flux from the adjacent channels are set off by a plurality of pairs of inductors in one low pass filter. The low pass filter of each channel is formed by the same construction and the same circuit. The inductors are arranged in a manner that center axes of coils of the two corresponding pairs of inductors in the adjacent channels are located at vertexes of a rectangular parallelogram, and combinations of the winding directions of the coils of the corresponding inductors of the adjacent channels are set to the same direction and the opposite directions every other inductor.

Abstract: An integrated high-voltage linear amplifier IC with reduced power dissipation, faster operation, and small die size, comprising a low side well and a floating high side well; an error amplifier for receiving a noise signal; a level shifting circuit in the low side well for outputting a current mode error signal based on the noise signal to the high side well in differential current mode for noise reduction; and a drive circuit in the high side well. A voltage/current converter receives a voltage mode error signal based on the noise signal and supplies the current input signal. Current mirror circuitry and the drive circuit in the high side well outputs a sum current derived from the current mode error signal for driving external power devices.

Abstract: A process for preparing a purified refolded monomer or dimer of a bone-derived factor, which comprises subjecting an inclusion body of a bone-derived factor produced by genetic engineering to the following steps a) to c) in sequence: a) introducing a polynucleotide encoding a bone morphogenetic factor into a bacterium, expressing said bone morphogenetic factor in the form of an inclusion body, recovering said inclusion body and treating it with a denaturing agent to obtain a solubilized monomer, b) treating the solubilized monomer without purification directly with a refolding solution to obtain a refolded monomeric bone morphogenetic factor, c) subjecting the refolded monomeric bone morphogenetic factor to purification.

Abstract: An active EMI filter for reducing common mode current in a circuit comprising a rectifier coupled to an AC network, the rectifier supplying DC power to a DC bus, the DC bus feeding an inverter stage for providing AC power to a load, the load having a ground return line to a ground connection of the AC network, the active filter comprising: a transistor switching stage coupled across the DC bus, a current sensor coupled to the DC bus for sensing the common mode current flowing in the DC bus and proportional to the common mode current flowing in the ground return line from or to the load, the current sensor having inputs coupled to respective legs of the DC bus and an output driving the transistor switching stage, the transistor switching stage comprising two transistors driven by said output of the current sensor whereby one of said transistors is turned on by said current sensor output depending on the direction of common mode current in said DC bus, a capacitor coupling said transistor switching stage and sa

Abstract: An active EMI filter senses current in a ground line as a voltage across a capacitor coupled to the ground line. The EMI filter senses common mode voltage and determines a difference between the common mode voltage and noise to provide an output to the ground line to reduce the difference.

Abstract: An active EMI filter senses current in a ground line or a power transmission line as a voltage cross a capacitor coupled to the line. The EMI filter senses common mode voltage and determines a difference between the common mode voltage and noise to provide an output to drive the difference to zero. The resulting active closed loop EMI filter produces good EMI dampening with greatly increased performance over a current transformer type EMI filter. A voltage regulator for the error amplifier improves noise reduction while increasing filter efficiency. The active EMI filter operates in a wide linear range that is greater than that of an equivalent current transformer circuit, while providing low cost and reliability.

Abstract: A motor drive system control provides global closed loop feedback to cooperatively operate system components to adaptively reduce noise and provide noise cancellation feedback. An active EMI filter reduces differential and common mode noise on an input and provides a noise level indication to a system controller. Power switches in both a power converter and power inverter are cooperatively controlled with dynamic dv/dt control to reduce switching noise according to a profile specified by the controller. The dv/dt control is provided as an analog signal to a high voltage IC and codified as a pulse width for a level shifting circuit supplying control signals to the high voltage gate drive. A noise extraction circuit and technique obtain fast noise sampling to permit noise cancellation and adaptive noise reduction.

Abstract: A power amplifying device promptly detects an abnormal condition of a load and permits protection of an output without causing power loss. A test signal having a predetermined frequency and signal level is supplied to an amplifier, and the output level is measured. The measured level is compared with the output level that is projected when the test signal is supplied with an appropriate load connected to the amplifier so as to detect a load condition. If a determination result indicates that the load is short-circuited or released, then the operation of the amplifier is promptly interrupted.

Abstract: A D-class power amplifier of two channels in which an increase in power voltage due to a regenerative current is prevented and a high efficiency in utilization of electric power is attained. Two D-class power amplifying circuits included in the D-class power amplifier of the two channels are constructed by opposite phases. A preprocess is performed only to low frequency components of input signals so that they have a substantially equal amplitude in the two channels, and the resultant low frequency components are supplied to the D-class power amplifying circuits, respectively. The other ends of loads connected to the D-class power amplifying circuits are connected to a neutral potential point of the power voltage.