Operating Quadrants

Figure 4-2 shows the operating locus of your power supply in three quadrants. The area in quadrant 1 shows the operating locus defined by the voltage and current settings of each output. The characteristics shown for quadrant 1 incorporate remote sensing and include the maximum available sense voltage plus load lead drop. The area in quadrant 2 indicates the locus where each output can operate as a current sink. You cannot program current limit values in quadrant 2. (Figure 4-3 shows the current sink characteristics at voltages below 2.0 V in greater detail.) The area in quadrant 4 illustrates the reverse polarity diode characteristics of each output. Do not operate any output with reverse-voltage currents that are greater than the maximum rating of the output.

Notice that the L shaped characteristics in quadrant 1 of Figure l-l consists of two overlapping ranges-a high voltage/low current range, and a low voltage/high current range. The power supply always limits its settings to within the boundaries of these ranges. Attempting to program voltage or current values that are greater than the maximum programmable values for a given output results in an error message and the values are ignored by the supply.

Range Selection

When a voltage and current are specified, each of which is within the maximum programmable value but whose combination lies outside the L shaped operating locus, the power supply will automatically select the operating range based on the value of the last VSET or ISET parameter that was programmed. The other parameter will automatically be reprogrammed to the maximum rating of the selected range. Chapter 5 includes an example of automatic range selection (also referred to as range switching).

Once your power supply output is operating in a given range, it will not automatically switch to the other range because of a change in the load. The only time an output switches operating ranges is in response to a command from either the front panel or the HP-IB that changes the voltage or current settings. For the output to switch ranges, the voltage or current setting must specify a value that is inside the operating locus of the other range. If the value sent is common to both ranges, no range switching occurs.

Protection Features

Protective circuitry within the supply can limit or turn off an output in the event of an abnormal condition. The activated protection feature can be determined by observing the front panel display area. You can also read back the status of the supply over the HP-IB. The following protection features are implemented:

OVERVOLTAGE -- shorts the output by firing an SCR crowbar and sets zero volts and minimum current on an output if any of the following conditions are present:

1.The output voltage exceeds the programmed overvoltage trip point. or

2.The voltage from the +V output terminal to the + S terminal or from the -S terminal to the -V output terminal exceeds

1.5V (applies to remote sensing only).

or

3. A trip signal is received on the output's OV terminals.

or

4. The output's fixed overvoltage circuit is activated.

The OV trip point can be programmed up to 23 V on a low voltage output and up to 55 V on a high voltage output. When an overvoltage occurs, the word OVERVOLTAGE appears in the front panel display and the OV status bit is set for that output. Chapter 5 explains how to program the overvoltage trip level.

44 Output Connections and Operating Information

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HP 6621A, 6623A, 6624A manual Protection Features, Operating Quadrants, Range Selection

6624A, 6621A, 6623A specifications

The HP 6623A, 6621A, and 6624A are precision DC power supplies widely recognized for their reliability and performance in various laboratory and industrial applications. These models are part of HP's 662X series, designed to cater to the needs of engineers, researchers, and technicians who require accurate power sources for their testing and development activities.

The main features of the HP 6623A, 6621A, and 6624A include their high stability, low ripple, and excellent load regulation, ensuring that the output voltage and current remain stable during testing. The power supplies provide multiple output channels, allowing users to power multiple devices simultaneously. The flexibility in setting voltage and current levels makes these models ideal for a wide range of applications, including semiconductor testing, device characterization, and system integration.

One of the standout technologies in the HP 662X series is the use of smart design techniques that minimize noise and enhance output performance. These power supplies incorporate advanced feedback mechanisms to maintain steady output, even under varying load conditions. Additionally, they feature programmable outputs, which means users can adjust the output levels through a connected computer or control system, streamlining the testing process and improving efficiency.

The HP 6623A model offers three independent outputs, with total power capabilities of 40 watts. It includes a 0-20V output, which can deliver up to 2A of current, along with two additional outputs that are adjustable. The 6621A provides a single output option, delivering a maximum of 20V and 2A, making it well-suited for simple applications where a single power source is required. In contrast, the HP 6624A stands out with its four independent output channels, providing a total of 60 watts, making it the most versatile of the three models.

Characteristics of these power supplies include user-friendly interfaces, allowing for easy configuration and monitoring of settings. LED indicators provide real-time feedback on voltage and current levels, enabling users to quickly assess the performance of their tests. Moreover, built-in protection features safeguard both the power supply and the connected devices from overvoltage and overcurrent conditions.

Overall, the HP 6623A, 6621A, and 6624A power supplies embody advanced engineering and design, making them invaluable tools for professionals looking for high-quality, reliable power sources for their electronic testing needs.