LS5870-0D View Datasheet(PDF) - Power-One Inc.

Part Name

Description

Manufacturer

LS5870-0D

100 Watt AC-DC Converters with PFC

Power-One Inc. 

Cassette Style

100 Watt AC-DC Converters

S Series PFC

V ACFAIL Signal (VME)

Available for units with Uo1 = 5.1V

This option defines an undervoltage monitoring circuit for

the input or input and main output voltage equivalent to op-

tion D and generates the ACFAIL signal (V signal) which

conforms to the VME standard.

The low state level of the ACFAIL signal is specified at a

sink current of IV ≤ 48 mA to UV ≤ 0.6 V (open-collector out-

put of a NPN transistor). The pull-up resistor feeding the

open-collector output should be placed on the VME back

plane.

After the ACFAIL signal has gone low, the VME standard

requires a hold-up time th of at least 4 ms before the 5.1 V

output drops to 4.875 V when the output is fully loaded.

This hold-up time th is provided by the internal input capaci-

tance. See also fig.: Hold-up Time versus Output Power.

Table 20: Undervoltage monitor functions

V output

(VME compatible)

V2

Monitoring

Ui

U o1

Minimum adjustment

range of threshold level

Uti

Uto

yes no 355V DC 1

–

V3

yes yes 355V DC 1 0.95...0.985 Uo1 2

1 Option D monitors the boost regulator output voltage. The trig-

ger level is adjusted in the factory to 355 V DC.

2 Fixed value between 95% and 98.5% of Uo1.

Option V operates independently of the built-in input under-

voltage lock-out circuit. A logic "low" signal is generated at

pin 20 as soon as one of the monitored voltages drops be-

low the preselected threshold level Ut. The return for this

signal is Vo1–. The V output recovers when the monitored

voltage(s) exceed(s) Ut + Uh. The threshold level Uti is ad-

justed in the factory to 355 V DC. The threshold level Uto

either is adjusted during manufacture to a determined cus-

tomer specified value.

V output (V2, V3):

Connector pin V is internally connected to the open collec-

tor of a NPN transistor. The emitter is connected to the

negative potential of output 1. UV ≤ 0.6 V (logic low) corre-

sponds to a monitored voltage level (Ui and/or Uo1) <Ut.

The current IV through the open collector should not ex-

ceed 50 mA. The NPN output is not protected against ex-

ternal overvoltages. UV should not exceed 60 V.

Ui, Uo1 status

Ui or Uo1 < Ut

Ui and Uo1 > Ut + Uh

V output, UV

low, L, UV ≤ 0.6 V at IV = 50 mA

high, H, IV ≤ 25 µA at UV = 5.1 V

11009

Vo1+

Rp

IV

V

UV

Vo1–

Fig. 39

Output configuration of options V2 and V3

Edition 01/01.2001

25/27

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