SILINKPS-EVB Silicon Laboratories Inc, SILINKPS-EVB Datasheet - Page 2

• Manufacturer Part Number: SILINKPS-EVB
• Description: DAUGHTER CARD PROSLIC PS
• Manufacturer: Silicon Laboratories Inc
• Type: DC/DC Switching Converters, Regulators & Controllersr

Specifications of SILINKPS-EVB

• Accessory Type: Power Supply Board
• Input Voltage: 9 V to 15 V
• Output Voltage: 3.3 V, 5 V
• Product: Power Management Modules
• Supply Current: 2.5 A
• For Use With/related Products: Silicon Labs' ProSLIC and DAA Eval Boards
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Contains lead / RoHS non-compliant

High-Voltage Battery Supply
The schematic for this power circuit is illustrated in
Figure 3 on page 4. The LTC3704 dc-dc controller IC is
used to drive an external MOSFET and a multi-tap
transformer to create four equal high-voltage negative
outputs, VNEG (See Table 2), from the dc input supply.
Only one output is regulated via close-loop feedback.
The other three outputs are cross-regulated to the first
output via the transformer ratio. The LTC3704’s
negative feedback input eliminates inverting circuitry
when creating negative outputs from a positive input.
The six-winding 1:1 ratio transformer is configured in a
manner that minimizes the need for multiple high-
voltage output filter capacitors.
VNEG Voltage Adjustment
The transformer, T1, has four secondary windings, each
producing an equal negative voltage, VNEG. These four
windings are connected in series through the diode
rectifying circuits to produce four negative voltage
potentials with voltage levels equal to multiples from 1
to 4 of the VNEG magnitude. Any adjustment made to
the VNEG has a direct effect on the voltage levels on all
negative outputs.
Resistor R23 can be modified to realize custom output
voltages as defined in the following equation.
VNEG = (1.23 x R23/R22) + 1.23
The SiLinkPS-EVB is shipped with R23 = 33.2 k and
R22 = 1.65 k for VNEG equal to 26 V.
The VBLO is normally used for off-hook state and its
voltage level can be programmed by the setting on the
Si3211/Si3212
Si3220/Si3232
Si3225
Dual ProSLIC
Part Number
Table 2. Popular Application Configurations and Jumper Settings
PK-PK Ringing
N/A (external)
Amplitude
75 V
90 V
VBRNG
4xVNEG
–104 V
—
—
Rev. 0.2
3xVNEG
2xVNEG
–78 V
–52 V
VBHI
—
JP7 jumper. The voltage on the VBHI and VBRNG
outputs can be programmed by moving the jumper
settings on JP2, JP3, and JP4. Table 2 provides several
popular configurations and the required jumper settings.
Frequency Adjustment
The LTC3704 can be configured to run at switching
frequencies from 50 kHz to 1 MHz allowing flexibility to
choose the optimal efficiency/cost point for each
specific application. Resistor R18 programs the
switching frequency according to the characteristic
curve shown in Figure 2.
Figure 2. Timing Resistor R18 Value
VNEG
VNEG
–26 V
VNEG
VBLO
1000
–26 V
–26 V
100
10
0
100
JP2
2–3
1–2
2–3
200
300
FREQUENCY (kHz)
400
JP3
2–3
—
—
500
600
JP4
1–2
2–3
—
700
800
JP7
2–3
2–3
2–3
900
AN74
1000
2