Vicor Corp. Tel: 800-735-6200, 978-470-2900 Fax: 978-475-6715

HAM, Harmonic Attenuator Module

Rev. 1.1

Page 2 of 6

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• L1 and L2/N (VI-HAM):

These pins are to be connected to the AC mains

output of a suitable EMI/RFI filter (Vicor

P/N 07818 or equivalent). Do not connect an

X capacitor across these pins as power factor

correction will be slightly degraded.

• +IN, –IN (VI-HAMD, VI-BAMD):

These pins are connected to the output of the external

bridge rectifier.

• Gate Input (VI-HAM):

This pin disables the boost converter only. Rectified

line current may still be present on the output. This pin

does not provide the same function as the gate input

pin of VI-200/VI-J00 modules. The user should not

make any connection to this pin.

• Gate Input (VI-HAMD):

This pin serves as a rectified AC following pin for

power factor correction synchronization to line. This

connection must be made through the synchronization

diodes between the line filter and bridge rectifier

(see Fig. 10).

• Gate Input (VI-BAMD):

The Gate Input pin is an interface pin to the Gate Out

pin of a VI-HAM, VI-HAMD or VI-BAMD

depending on configuration. The user should not make

any other connection to this pin.

• Gate Output:

The Gate Output pin is an interface pin to BAMDs;

the user should not make any other connection to

this pin.

• +Output and -Output and Holdup Capacitor:

These outputs should be connected to the respective

inputs of Vicor DC-DC converters. In addition, an

external holdup capacitor of 1000 µF with a minimum

voltage rating of 450Vdc, is required across the

output for 16 ms ride through time at 600W (500 µF

for 300W, etc). Do not exceed 3000 µF of total

output capacitance. Lower values of capacitance may

be used for reduced holdup requirements, but not less

than 330 µF. Lower capacitance values may degrade

power factor specifications.

• Auxiliary Supply (A/S):

The VI-HAM and VI-BAMD contain an internal low

voltage output (A/S) that may be used to power

primary side logic. This output is 19-23Vdc,

referenced to -OUT, at 3 mA max. Do not overload or

short this output as the VI-HAM will fail. A typical

use for A/S is to power an optical coupler that isolates

the Power OK signal.

• Power OK (P/OK)

P/OK is a monitor signal that indicates the status of

the AC mains and the DC output voltage of the VI-HAM.

P/OK, during normal operation, is an active low (see

Fig. 6). In the event AC mains or DC output fails, this

pin goes to an open circuit state. P/OK is asserted

when the output bus voltage is within normal operating

range and 20-25 ms after DC-DC converters are

enabled by the Module Enable output of the VI-HAM.

This provides sufficient time for the converters to turn

on and their outputs to stabilize prior to P/OK being

asserted. When the AC mains is removed and the

output of the VI-HAM drops below 230V, P/OK goes

to an open circuit state. When the output voltage drops

below 195V the converters are disabled via Module

Enable. P/OK will provide power fail warning at least

1 ms prior to converter shutdown.

• Module Enable (E/O)

The Module Enable output is used to disable the

DC-DC converters until there is sufficient energy in

the holdup capacitor (240V) to support normal

operation, while limiting inrush current. Module

Enable must be connected to the Gate Input of all

driver DC-DC converters. It is not necessary to

connect this pin to boosters as they are controlled by

their respective driver. If the AC mains fail, Module

Enable goes low when the DC output of the VI-HAM

drops below 195V. Failure to connect Module Enable

may result in the output of the VI-HAM latching low

during turn-on.

LOGIC

E/O

-OUT

S

G

D

+ OUT

P/OK

– OUT

E/O

A/S

18 kΩ, 1/4W

"Power OK" Status

Low = OK

A/S

-OUT

≤ 3mA

19 - 23V

+

–

Pin Function Description

Outputs

VI-200

DC-DC

Converter(s)

Rectified Line

Module

Enable

DC

Output

of HAM

Power OK

AC

Mains

120V

RMS

Boost Voltage

195

Vdc

240

Vdc

Off at

195

Vdc

Off at

230

Vdc

230

Vdc

25 ms

10 ms

50

100

150

200

250

300

Output Voltage

as a Function

of Input Voltage

Vac

400Vdc

350Vdc

300Vdc

250Vdc

200Vdc

150Vdc

100Vdc

50Vdc

25

75

125

175

225

275

80Vac

85Vac

260Vdc

152Vac

Operating Region

250Vac

264Vac

46V

Boost

296

Vin x 2

Figure 3 • Functional Timing Diagram

Figure 4 • Input Voltage vs. Output Voltage

Figure 5 • Auxiliary Supply (A/S)

Figure 6 • Power OK (P/OK)

Figure 7 • Enable/Output (E/O)

LOGIC

P/OK

-OUT

S

G

D

Active power factor correctors incorporate a

boost regulator which must operate over a range

of incoming AC line voltages. Conventionally,

the output voltage of the boost regulator is set

to a value greater than the maximum anticipated

peak value of the incoming AC line.

Vicor varies the output voltage of the VI-HAM

as a function of incoming AC line voltage

(see Fig. 4, patent applied for). On a nominal

120Vac line the output voltage of the VI-HAM

is 260Vdc — well within the input operating

voltage range of standard Vicor converters.

As input line increases, so does the VI-HAM

output voltage; at 220Vac the delivered voltage

will be about 350V. For any given input line

voltage, the VI-HAM maintains enough

headroom between the output voltage and peak

input voltage to ensure high quality active

power factor correction without unnecessarily

sacrificing operating efficiency.

VI-HAM Protection Features

Overtemperature Shutdown

The VI-HAM incorporates overtemperature

shut-down, and is designed to shut down when

the temperature of the baseplate exceeds

90–100°C. It is not safe to run the VI-HAM

for extended periods above its maximum

operating temperature of 85°C.

Short Circuit Protection

The VI-HAM contains a short circuit shutdown

function. Operation of this function does not

clear the input fuse and the output will resume

normal operation after removal of the short.

A small period of time may be required to

allow for cooling of an internal PTC.

Overcurrent protection is provided by the

Vicor DC-DC converters.

Output Overvoltage Protection

The VI-HAM contains output overvoltage

protection. In the event the output voltage

exceeds approximately 420Vdc, the boost will

decrease to maintain 420Vdc on the output.

When the peak of the AC line exceeds 420V

(approximately 293Vac) the boost will have

been reduced to zero. Beyond this the protection

circuit will be enabled and the output voltage

will decrease.