Pisces II Series, Page 3

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Part No. 02-007 Rev. 3.0–061004

Undervoltage Lockout

30

32

36

34

40

38

Input Voltage (V)

Voltage

Rising

Voltage

Falling

Overvoltage Lockout

75

76

78

77

80

79

Input Voltage (V)

Voltage

Rising

Voltage

Falling

•Patented single-stage power conversion architecture,

control, and magnetic design allow unprecedented power

density and efficiency in an isolated power supply.

• An advanced microcontroller reduces parts count while

adding features, performance, and flexibility in the design.

•Low common-mode noise as a result of lower capacitance

in the transformer from balanced winding design.

Protection and Control

Valid Input Voltage Range:

The converter measures the input voltage and will not

allow operation outside of the input voltage

specification. As shown by the graphs, hysteresis is

added to both the high and low voltage to prevent the

converter from turning on and off repeatedly when the

voltage is held near either voltage extreme. At low line

this assures the maximum input current is not exceeded;

at high line this assures the semiconductor devices in

the converter are not damaged by excessive voltage

stress.

ON/OFF Logic Option:

The ON/OFF control logic can be either Negative

(standard) or Positive to enable the converter. For

Negative logic, bring the ON/OFF pin to less than 1.0V

with respect to the –INPUT pin to enable the converter.

The pull-down must be able to sink 100

µA. For

Positive logic, bring the ON/OFF pin to greater than

4.0V with respect to the –INPUT pin and be limited to

less than 10V. To request the Positive logic version, add

the suffix (P) to the standard part number. The ON/OFF

pin has a built-in pull up resistor of approximately

100k

Ω to +5V.

Application Notes