Chapter 2 General Information
Output Connections
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2
Stability
Using remote sensing under certain combinations of load lead lengths and
large load capacitances may cause your application to form a filter, which
becomes part of the voltage feedback loop. The extra phase shift created by
this filter can degrade the power supply’s stability, resulting in poor transient
response or loop instability. In severe cases, it may cause oscillations. To
minimize this possibility, keep the load leads as short as possible and twist
them together. As the sense leads are part of the power supply’s programming
feedback loop, accidental open-connections of sense or load leads during
remote sensing operation have various unwanted effects. Provide secure and
permanent connections.
CV Regulation
The voltage load regulation specification in chapter 8 applies at the output
terminals of the power supply. When remote sensing, add 5 mV to this
specification for each 1 V drop between the positive sensing point and (+)
output terminal due to the change in load current. Because the sense leads are
part of the power supply’s feedback path, keep the resistance of the sense leads
at or below 0.5
W
per lead to maintain the above specified performance.
Output Rating
The rated output voltage and current specifications in chapter 8 apply at the
output terminals of the power supply. With remote sensing, any voltage
dropped in the load leads must be added to the load voltage to calculate
maximum output voltage. The performance specifications are not guaranteed
when the maximum output voltage is exceeded. If the excessive demand on
the power supply forces the power supply to lose regulation, the
Unreg
annunciator will turn on to indicate that the output is unregulated.
Output Noise
Any noise picked up on the sense leads also appears at the output of the power
supply and may adversely affect the voltage load regulation. Twist the sense
leads to minimize external noise pickup and run them parallel and close to the
load leads. In noisy environments it may be necessary to shield the sense leads.
Ground the shield at the power supply end only. Do not use the shield as one
of the sense conductors.
