Principles of Operation - 4

The output is programmed off.

An overvoltage condition is detected (OV_Detect* signal is received).

The line voltage falls below 90 volts (approximately).

Current readback is provided by three separate circuits. The previously discussed high range current signal (Imon_H) returns the high range current measurement. When the unit is operating in the low current readback mode, a separate low range current shunt and amplifier provides low-current readback via the Imon_L signal. The Range_Select signal drives shunt clamps Q304 and Q305, which clamp the voltage across RmLo to approximately 1.8 V. A third current readback circuit is available on the Agilent 66332A unit. It consists of a high bandwidth current amplifier that returns dynamic current measurements from the output filter capacitor via the Imon_P signal. Note that the Imon_H and the Imon_P signal are combined to return the actual output current measurement.

An overvoltage detect circuit compares the output voltage to the programmed overvoltage setting. When the output exceeds the programmed setting, the OV_Detect* signal goes low, which informs the logic array that an OV condition has occurred. The crowbar control circuit is enabled when the OV_SCR* signal is received. When an overvoltage condition occurs, the SCR control circuit generates the OV signal, which causes the following actions to occur:

1.The SCR fires, shorting the supply's output.

2.The microprocessor circuits are notified of the OV condition (OV_Detect* is low) in order to program the output off, turn off the gain stage bias, and update the status of the unit.

3.When a output protection clear command is executed, the microprocessor circuits resets the OV circuits, turns on the gain stage bias, and programs the output to its previous level.

The fan driver control circuit provides the DC voltage to operate the cooling fan. The Fan_Prog signal from the secondary interface circuit varies this voltage according to the ambient and heatsink temperature as well as the output voltage and current of the supply.

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Agilent Technologies 66332A, 6634B, 6633B, 6632B service manual Principles of Operation
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6632B, 6633B, 66332A, 6634B specifications

Agilent Technologies, a leader in electronic test and measurement solutions, offers a range of power supplies designed to meet various application needs. Notable models include the 6632B, 6634B, 66332A, 6633B, and 6612C. Each of these units provides unique features and technologies that cater to researchers, engineers, and technicians in the industry.

The Agilent 6632B is a single-output DC power supply that delivers up to 30V and 3A. It is known for its excellent load regulation and low noise, making it ideal for sensitive electronic testing. The model includes built-in voltage and current measurement capabilities, allowing users to monitor output conditions in real time. The 6632B is commonly used in laboratory environments, educational institutions, and manufacturing lines.

Moving to the 6634B, this model offers dual-output capabilities with a maximum output of 30V and 6A. This versatility enables simultaneous powering of two different devices or circuit sections. It also features parallel and series operation options, allowing users to create a custom power supply configuration for specific applications. With a programmable interface, the 6634B simplifies test automation, ensuring efficiency in extensive testing scenarios.

The Agilent 66332A stands out with its precision and high performance. This power supply provides three outputs—two programmable and one fixed—yielding flexible power configurations. Its intuitive user interface allows easy adjustment of voltage and current settings. The device is equipped with extensive protection features to safeguard both the power supply and the connected load against faults. It is an excellent choice for complex testing setups that require reliable power.

The 6633B model offers a high-performance power supply with dual outputs, similar to the 6634B but with enhanced specifications. It can provide up to 40V and 2A per channel, delivering precision for demanding applications. This model is particularly suited for industries focused on high-reliability applications, such as telecommunications and aerospace.

Lastly, the Agilent 6612C is a compact and lightweight power supply providing single-output up to 60V and 2A. This model is designed for simplicity and ease of use, making it an excellent choice for portable applications. The 6612C’s unique characteristics include a compact design and user-friendly controls, which facilitate operation in field settings.

In summary, Agilent Technologies’ power supply models—6632B, 6634B, 66332A, 6633B, and 6612C—offer an array of features that cater to a wide range of testing and research needs, ensuring reliable power delivery in various contexts.
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