UC2901Enhanced Product Isolated Feedback Generator | Integrated Circuits (ICs) | 9 | Active | The UC1901 family is designed to solve many of the problems associated with closing a feedback control loop across a voltage isolation boundary. As a stable and reliable alternative to an optical coupler, these devices feature an amplitude modulation system which allows a loop error signal to be coupled with a small RF transformer or capacitor.
The programmable, high-frequency oscillator within the UC1901 series permits the use of smaller, less expensive transformers which can readily be built to meet the isolation requirements of today's line-operated power systems. As an alternative to RF operation, the external clock input to these devices allows synchronization to a system clock or to the switching frequency of a SMPS.
An additional feature is a status monitoring circuit which provides an active-low output when the sensed error voltage is within ±10% of the reference. The DRIVERA output, DRIVERB output, and STATUS output are disabled until the input supply has reached a sufficient level to allow proper operation of the device.
Since these devices can also be used as a DC driver for optical couplers, the benefits of 4.5 to 40V supply operation, a 1% accurate reference, and a high gain general purpose amplifier offer advantages even though an AC system may not be desired.
The UC1901 family is designed to solve many of the problems associated with closing a feedback control loop across a voltage isolation boundary. As a stable and reliable alternative to an optical coupler, these devices feature an amplitude modulation system which allows a loop error signal to be coupled with a small RF transformer or capacitor.
The programmable, high-frequency oscillator within the UC1901 series permits the use of smaller, less expensive transformers which can readily be built to meet the isolation requirements of today's line-operated power systems. As an alternative to RF operation, the external clock input to these devices allows synchronization to a system clock or to the switching frequency of a SMPS.
An additional feature is a status monitoring circuit which provides an active-low output when the sensed error voltage is within ±10% of the reference. The DRIVERA output, DRIVERB output, and STATUS output are disabled until the input supply has reached a sufficient level to allow proper operation of the device.
Since these devices can also be used as a DC driver for optical couplers, the benefits of 4.5 to 40V supply operation, a 1% accurate reference, and a high gain general purpose amplifier offer advantages even though an AC system may not be desired. |
| Power Management - Specialized | 4 | Active | |
| Supervisors | 8 | Obsolete | |
| Integrated Circuits (ICs) | 7 | Active | |
UC290735V load share controller, -40°C to 85°C | Power Management - Specialized | 6 | Active | The UCx907 family of load share controller ICs provides all the necessary features to allow multiple-independent-power modules to be paralleled such that each module supplies only its proportionate share to total-load current.
This sharing is accomplished by controlling each module’s power stage with a command generated from a voltage-feedback amplifier whose reference can be independently adjusted in response to a common-share-bus voltage. By monitoring the current from each module, the current share bus circuitry determines which paralleled module would normally have the highest output current and, with the designation of this unit as the master, adjusts all the other modules to increase their output current to within 2.5% of that of the master.
The current share bus signal interconnecting all the paralleled modules is a low-impedance, noise-insensitive line which will not interfere with allowing each module to act independently should the bus become open or shorted to ground. The UC3907 controller will reside on the output side of each power module and its overall function is to supply a voltage feedback loop. The specific architecture of the power stage is unimportant. Either switching or linear designs may be utilized and the control signal may be either directly coupled or isolated though the use of an optocoupler or other isolated medium.
Other features of the UC3907 include 1.25% accurate reference: a low-loss, fixed-gain current-sense amplifier, a fully differential, high-impedance voltage sensing capability, and a status indicator to designate which module is performing as master.
The UCx907 family of load share controller ICs provides all the necessary features to allow multiple-independent-power modules to be paralleled such that each module supplies only its proportionate share to total-load current.
This sharing is accomplished by controlling each module’s power stage with a command generated from a voltage-feedback amplifier whose reference can be independently adjusted in response to a common-share-bus voltage. By monitoring the current from each module, the current share bus circuitry determines which paralleled module would normally have the highest output current and, with the designation of this unit as the master, adjusts all the other modules to increase their output current to within 2.5% of that of the master.
The current share bus signal interconnecting all the paralleled modules is a low-impedance, noise-insensitive line which will not interfere with allowing each module to act independently should the bus become open or shorted to ground. The UC3907 controller will reside on the output side of each power module and its overall function is to supply a voltage feedback loop. The specific architecture of the power stage is unimportant. Either switching or linear designs may be utilized and the control signal may be either directly coupled or isolated though the use of an optocoupler or other isolated medium.
Other features of the UC3907 include 1.25% accurate reference: a low-loss, fixed-gain current-sense amplifier, a fully differential, high-impedance voltage sensing capability, and a status indicator to designate which module is performing as master. |
| Battery Chargers | 5 | Active | |
| Power Management (PMIC) | 5 | Active | |
| Integrated Circuits (ICs) | 1 | Obsolete | |
UC29432Precision analog controller, -25C to 85C | Power Management (PMIC) | 7 | Active | The UC39432 is an adjustable precision analog controller with 100mA sink capability if the ISET pin is grounded. A resistor between ISET and ground will modify the transconductance while decreasing the maximum current sink. This will add further control in the optocoupler configuration. The trimmed precision reference along with the non-inverting error amplifier inputs are accessible for custom configuration. A sister device, the UC39431 adjustable shunt regulator, has an on-board resistor network providing six preprogrammed voltage levels, as well as external programming capability.
The UC39432 is an adjustable precision analog controller with 100mA sink capability if the ISET pin is grounded. A resistor between ISET and ground will modify the transconductance while decreasing the maximum current sink. This will add further control in the optocoupler configuration. The trimmed precision reference along with the non-inverting error amplifier inputs are accessible for custom configuration. A sister device, the UC39431 adjustable shunt regulator, has an on-board resistor network providing six preprogrammed voltage levels, as well as external programming capability. |
UC29504-A half bridge bipolar switch | Full Half-Bridge (H Bridge) Drivers | 2 | Active | This device is a monolithic integrated circuit designed to provide high-current switching with low saturation voltages when activated by low-level logic signals. Source and sink switches may be independently activated without regard to timing as a built-in interlock will keep the sink off if the source is on.
This driver has the high current capability to drive large capacitive loads with fast rise and fall times; but with high-speed internal flyback diodes, it is also ideal for inductive loads. Two UC2950s can be used together to form a full bridge, bipolar motor driver compatible with high frequency chopper current control.
This device is a monolithic integrated circuit designed to provide high-current switching with low saturation voltages when activated by low-level logic signals. Source and sink switches may be independently activated without regard to timing as a built-in interlock will keep the sink off if the source is on.
This driver has the high current capability to drive large capacitive loads with fast rise and fall times; but with high-speed internal flyback diodes, it is also ideal for inductive loads. Two UC2950s can be used together to form a full bridge, bipolar motor driver compatible with high frequency chopper current control. |
