KEPCO BHK-MG 40W (Half Rack) Series - Manual (Page 92)

3-48
BHK-1/2-MG 121313
3.8.5.1 VOLTAGE MODE
With the power supply in voltage mode (see Figure 3-17) and the digitally programmed output
voltage at zero, varying the external current source from 0 to 1mA causes the output voltage of
the power supply to vary linearly from 0 to E
O
max with a slope of (E
O
max) volts per mA. The fol-
lowing equations give the output voltage as determined by the external current source I
EXT
.
ANALOG PROGRAMMING, DIGITAL PROGRAMMING = 0:
Eo = (–1)I
EXT
x (10K) x (–1) (10K/10K) x (–1) (R/10K)
= –(R) x | I
EXT
| (V d-c)
where
R = Internal feedback resistance equal to correction resistance (K-ohms), determined by
Model (see Table 3-10).
I
EXT
= External current source (mA). This source can be either a d-c source or a function gen-
erator with an internal bias delivering a constant current. If the bias is not available from
the function generator, use the digital programming feature of the BHK-MG to provide
proper bias to avoid clipping waveform at the output of the power supply.
ANALOG PROGRAMMING COMBINED WITH DIGITAL PROGRAMMING:
Eo = –(R x | I
EXT
| ) – Eout
DP
(V d-c)
where
Eout
DP
= Output voltage programmed digitally (from either local keypad or remote GPIB bus)
(See above for definitions of R and V
EXT
.)
3.8.5.2 CURRENT MODE
With the power supply in current mode (see Figure 3-18) and the digitally programmed output
voltage at zero, varying the external current source from 0 to 1mA causes the output current of
the power supply to vary linearly from 0 to I
O
max with a slope of (I
O
max) mA per mA. The fol-
lowing equations give the output current as determined by the external current source I
EXT
.
ANALOG PROGRAMMING, DIGITAL PROGRAMMING = 0:
Io =
[ (–1) I
EXT
x (10K) x (–1) (10K/10K) x (–1/10) (10K/10K) ]/Rs
= –(1/Rs) x | I
EXT
| (mA d-c)
where
Rs =Internal shunt resistance (K-ohms), determined by Model (see Table 3-10).
(See above for definition of I
EXT
.)
ANALOG PROGRAMMING COMBINED WITH DIGITAL PROGRAMMING:
Io = –(1/Rs) x | I
EXT
| – Iout
DP
(mA d-c)
where
Iout
DP
= Output current programmed digitally (from either local keypad or remote GPIB bus)
(See above for definitions of Rs and I
EXT
.)