Datasheet

Hardware Overview

2.5 POWER RATING OF CONVERTER STAGE

All three DC/DC power stages in a Daughter Board can be loaded externally through

the output terminal blocks J4, J5 and J8. For loading any power stage externally, the

user must provide an auxiliary power source to the Daughter Board through input

terminal block J9.

2.5.1 Buck 1 Converter

The Buck 1 converter stage is rated for a maximum output current of 3 amps through

the J4 connector. The output voltage of the buck converter (VOUT1) can be pro-

grammed for 0V-5V output. The hardware gain [5k/(3.3k + 5k)] of the voltage feedback

of VOUT1 is provided by the resistor divider network of R11 and R12. The hardware

gain of the current feedback is provided by the current transformer (Tx1) with turns ratio

(1:60) and burden resistor R5. The circuitry consists of R6, R7, C7 and Q3, and

provides slope compensation for current feedback (Current Sense1).

2.5.2 Buck 2 Converter

The Buck 2 converter stage is rated for a maximum output current of 3 amps through

the J5 connector. The output voltage of the buck converter (VOUT2) can be pro-

grammed for 0V-5V output. The hardware gain [5k/(3.3k + 5k)] of the voltage feedback

of VOUT2 is provided by the resistor divider network of R29 and R30. The hardware

gain of the current feedback is provided by the current transformer (Tx2) with turns ratio

(1:60) and burden resistor R23. The circuitry consists of R24, R25, C14 and Q8, and

provides slope compensation for current feedback (Current Sense2).

2.5.3 Boost Converter

The Boost converter stage is rated for a maximum output current of 0.75 amps through

the J8 connector. The output voltage of the boost converter (VOUT3) can be

programmed up to a maximum output of 20V. The hardware gain [20k/(20k + 3.3k)] of

the voltage feedback of VOUT3 is provided by the resistor divider network of R55 and

R56. The hardware gain of the current feedback is provided by the current sense

resistor R53 (current sense boost/Current Sense3). The circuitry consists of R13, R14,

C20 and Q4 and provides slope compensation for current feedback

(current sense boost/Current Sense3).