DC Voltage Current Source/Monitor
6247C / 6247G
The 6247C/6247G is a DC voltage current source/monitor designed for evaluating high voltage semiconductors and LED luminaires that demand high efficiency and low power consumption, capable of outputting voltage up to +250 V and current up to ±320 mA. It provides high accuracy of ±0.02 % with 4½-digit source resolution and 5½-digit measurement resolution.
The 6247C/6247G features the well-established VSIM, ISVM, sweep and pulse generation functions. Also, leak current measurement up to 10 pA is possible. In addition, it is equipped with the various types of sweep functions such as linear, fixed, random and two slope linear sweep functions, the pulse measurement function with the minimum pulse width of 50 μs, the micro voltage and current measurement function with the minimum resolution of 10 μV or 10 pA, and the suspend function that controls the optimized output status. By using these functions, the 6247C/6247G can be widely used for evaluating or testing semiconductor and other electronic components in R&D fields and production lines.
Voltage source, current source, voltage measurement, current measurement and resistance measurement are available by specifying the source and measurement functions.
There are four source modes; DC, pulse, DC sweep, pulse sweep. Then, the sweep modes are classified into four sweep types: fixed sweep, linear sweep, random sweep (any type of waveform generation by user's programming), two slope linear sweep (linear sweep with step value switching). The minimum pulse width is 50 µs. The minimum cycle is 2 ms, or 500 µs without measurement.
In voltage or current source, the HI/LO limiter settings are very important. The 6247C/6247G has a function that can set the HI and LO limiters individually. Furthermore, for the voltage-limiter, both HI and LO limiters can be set homo-polar. This prevents a capacitor or a battery from being over-discharged. Also, it is suitable for evaluating devices such as LDs that are used at a constant current and do not tolerate reverse voltage application.
The 6247C/6247G can select from three output OFF statuses; STBY (output relay OFF), HiZ (output relay ON and high resistance), and LoZ (output relay ON and low resistance). Using this function can omit unnecessary relay ON/OFF operations, which extends the relay lifetime and improves the system throughout.
In addition, the setting of a suspend voltage (voltage in HiZ and LoZ status) can prevent transient current from being generated when connecting voltage sourcing devices such as batteries.
When a conventional generator or electronic load is connected with a battery, the output voltage is 0 V, and then the setting current starts flowing. In this case, the moment that it is connected, transient current sink occurs, causing unnecessary battery discharge. On the other hand, by setting the suspend voltage, the 6247C/6247G is connected in high-impedance state at the specified voltage and then the setting current flows. This prevents unnecessary discharge at the connection to the battery. For the 6247C/6247G, the source modes can be switched in such suspend status, which improves the throughput. (Continuous testing is possible without disconnecting DUTs.)
LED evaluation is done by ISVM (current source voltage measurement). When constant current is applied to a LED between 0 A and +IS, the output current becomes the setting current at the rising edge, but 0 A at the falling edge and the response time is very slow to discharge the device. To avoid this problem, current is applied between -IS and +IS. At this time, +VL is set to the forward voltage or higher and -VL to 0 V or minus several V to prevent reverse voltage application. The response when fifty white LEDs are connected in series is as follows:
+IS = +30 mA, -IS = -30 mA, +VL = +200 V, -VL = -5 V
Sample hold measurement is available in the pulse mode and the pulse sweep mode. Measurement holds an input signal immediately before pulse falling edge, and A/D conversion is implemented for integration time of 100 µs. This function enables precise values to be measured without setting the measurement delay time.