Normal Series Operation

Setting Voltage and Current. Turn the slave unit's CURRENT control fully clockwise. Adjust the master unit's controls to set the desired output voltage and current. The master supply operates in a completely normal fashion and may be set up for either con- stant voltage or constant current operation as required. Verify that the slave is in CV operation.

For auto-parallel operation of two supplies, the combined output voltage is the same as the master unit's voltage setting, and the combined output current is two times the master unit's current. In general, for two supplies, the auto-parallel output current(Io) is

Io = Im + Is = 2Im

where Im = master unit's output current Is = slave unit's output current

Proportional currents from auto-paralleled units require equal load-lead voltage drops. Connect each supply to the load using separate pairs of wire with length chosen to provide equal voltage drops from pair to pair. If this is not feasible, connect each supply to a pair of distribution terminals using equal- voltage-drop wire pairs, and then connect the distribution terminals to the load with a single pair of leads.

MASTER POWER SUPPLY

MASTER

LOCAL

M/S 1

M/S 2

SENSE

OUT

-S

CC VREF A1 A2

A4 A5

SLAVE

REMOTE

LOAD

SLAVE POWER SUPPLY

MASTER

LOCAL

M/S 1

M/S 2

SENSE

OUT

-S

CC VREF A1 A2

A4 A5

SLAVE

REMOTE

Figure 9. Auto-Parallel Operation of Two Supplies

Overvoltage Protection. Adjust the desired OVP shutdown limit using the master unit's OVP Adjust control. Set the slave units' OVP limits above the master's. When a master-unit shuts down, the master programs the slave units to zero voltage output. If a slave unit shuts down, it shuts only itself down. If the required cur- rent is great enough, the master will switch from CV to CC opera- tion.

Remote Sensing. To remote sense with auto-parallel operation, connect remote-sense leads only to the master unit according to the remote-sensing instructions.

Remote Analog Voltage Programming. To remote program with auto-parallel operation, set up only the master unit for remote pro-

gramming according to the remote-programming instructions.

MASTER POWER SUPPLY

+ _

MASTER

LOCAL

M/S 1 M/S 2

SENSE

OUT

-S

CC VREF A1 A2

SLAVE

REMOTE

LOAD

SLAVE POWER SUPPLY

+ _

MASTER

LOCAL

M/S 1 M/S 2

SENSE

OUT

-S

CC VREF A1 A2

SLAVE

REMOTE

SLAVE POWER SUPPLY

+ _

MASTER

LOCAL

M/S 1 M/S 2

SENSE

OUT

-S

CC VREF A1 A2

SLAVE

REMOTE

Figure 10. Auto-Parallel Operation of Three Supplies

Series operation of two or more power supplies can be accom- plished up to the output isolation rating of any one supply to obtain a higher voltage than that available from a single supply. Series connected supplies can be operated with one load across both supplies or with a separate load for each supply. These power supplies have a reverse polarity diode connected across the output terminals so that if operated in series with other sup- plies, damage will not occur if the load is short-circuited or if one supply is turned on separately from its series partners. When this connection is used, the output voltage is the sum of the voltages of the individual supplies. Each of the individual supplies must be adjusted in order to obtain the total output voltage. Figure 11 shows the rear panel switch settings and terminal connections for normal series operation of two supplies.

POWER SUPPLY

MASTER

LOCAL

M/S 1

M/S 2

SENSE

OUT

-S

VREF A1 A2 A3

A4 A5

SLAVE

REMOTE

LOAD

POWER SUPPLY

MASTER

LOCAL

M/S 1

M/S 2

SENSE

OUT

-S

VREF A1 A2 A3

A4 A5

SLAVE

REMOTE

Figure 11. Normal Series Operation of Two Supplies

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