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Remote Sensing. To remote sense with
Remote Analog Voltage Programming. To remote analog pro- gram with
AUTO-TRACKING OPERATON
Figure 14 and Figure 15 show two and three supplies connected in auto-tracking with their negative output terminals connected together as a common or ground point. For two units in auto- tracking a fraction R2/(R1+R2) of the output of the master supply is provided as one of the inputs to the comparison amplifier of the slave supply, thus controlling the slave's output. The master sup- ply in an auto-tracking operation must be the positive supply hav- ing the largest output voltage. Turn-up and turn-down of the power supplies are controlled by the master supply. In order to maintain the temperature coefficient and stability specifications of the power supply, the external resistor should be stable, low noise, low temperature.
Determining Resistors. External resistors control the fraction of the master unit's voltage that is supplied from the slave unit. For two units in auto-tracking the ratio R1 and R2 is
R2/(R1+R2 | = (Vs/Vm) |
Where Vm | = master output voltage |
Vs | = slave output voltage |
It is recommended to connect a 0.1 μF capacitor in paral- lel with R2 in two supplies operation or R2 and R4 in three supplies operation to ensure the stable operation.
Setting Voltage and Current. Use the master unit's VOLTAGE con- trol to set the output voltage from both units. When the master is in CV operation, the master's output voltage(Vm) is the same as its voltage setting, and the slave's output voltage for two units operation is Vm(R2/(R1+R2)). The VOLTAGE control of the slave unit is dis- abled. Set the CURRENT controls of master and slave units above the required currents to assure CV operation of master and slave units.
Overvoltage Protection. Set the OVP shutdown voltage in each unit so that it shuts down at a voltage higher than its output volt- age during
Remote Sensing. To include remote sensing with
Remote Analog Programming. To simultaneously remote pro- gram both units' output voltages, set up only the master unit for remote voltage programming according to the remote program- ming instructions. To vary the fraction of the output voltage contri- bution by the slave unit, connect a variable resistor in place of R2 in two units operation. To independently remote program each unit's output current setting, set up each unit for remote control of output current according to the instructions under "Remote Pro- gramming, Constant Current" paragraph.
MASTER POWER SUPPLY |
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MASTER |
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M/S 1 | M/S 2 | CV | CC | SENSE | +S | OUT | CV |
| CC | VREF A1 A2 | A3 | A4 A5 | |
SLAVE |
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| R1 | R2 |
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| LOAD |
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SLAVE POWER SUPPLY |
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MASTER |
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M/S 1 | M/S 2 | CV | CC | SENSE | +S | OUT | CV |
| CC | VREF A1 A2 | A3 | A4 A5 | |
SLAVE |
| REMOTE |
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Figure 14. Auto-Tracking Operation of Two Supplies
MASTER POWER SUPPLY |
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MASTER |
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M/S 1 | M/S 2 | CV | CC | SENSE | +S | OUT | CV |
| CC VREF A1 A2 | A3 | A4 | A5 | |
SLAVE |
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| REMOTE |
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| R1 | R2 |
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SLAVE POWER SUPPLY(S1) |
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MASTER |
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M/S 1 | M/S 2 | CV | CC | SENSE | +S | OUT | CV |
| CC VREF A1 A2 | A3 | A4 | A5 | |
SLAVE |
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| REMOTE |
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| R3 | R4 |
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SLAVE POWER SUPPLY(S2) |
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MASTER |
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M/S 1 | M/S 2 | CV | CC | SENSE | +S | OUT | CV |
| CC VREF A1 A2 | A3 | A4 | A5 | |
SLAVE |
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| Where | Vm = masters unit's output voltage |
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Vs1 = R1+ R2 | Vm |
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| R4 |
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| Vs1 = slave(S1) unit's output voltage |
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Vs2 = | Vs1 |
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| Vs2 = slave(S2) unit's output voltage |
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R3+ R4 |
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