Texas Instruments SLVU013 - Manual (Page 12)

Design Strategy
1-4
1.3 Design Strategy
The SLVP111–114 evaluation modules (EVMs) are optimized for 5-V main
input voltage and 6-A output current. The EVMs need an additional low current
12-V (30 mA max) input voltage for the controller. TI’s application report,
Providing a DSP Power Solution from 5 V or 3.3 V Only Systems, TI literature
number SPRA525 describes how one can implement a simple boost circuit for
5-V only input voltage applications. These EVMs are pin to pin compatible with
SLVP104/105/106/115 evaluation boards with 8 A output current, which
combine surface mount and through hole components. This surface mount
version has the same length, 2
″
, and width, 0.75
″
, but the height is significantly
lower, 0.375
″
versus 0.6
″
for through hole version.
The TI SLVP111–114 evaluation modules (EVM) provide synchronous buck
converter circuits for evaluating the capabilities of the TPS56xx family of ripple
regulator controllers. The EVM converters can provide proven, demonstrated
reference designs to aid in the rapid development of application-specific
synchronous buck converters. Output capacities of the EVM converters are
optimized for the Siliconix Si4410 power MOSFET device.
The 6-ampere output current level is a reasonable selection criteria for
powering circuit cards with multiple DSPs, and for providing the regulated
voltage to other hardware on the circuit card. Component size can be reduced
for designs requiring lower power levels.
The TPS56xx controllers each provide one of four popular output voltage
levels. The last two digits of the part number correlate to the set-point voltage
level: TPS5633 is the 3.3-V controller, TPS5625 is the 2.5-V controller,
TPS5618 is the 1.8-V controller, and TPS5615 is the 1.5-V controller. Many
digital devices, memories, and DSP I/O circuits use the 3.3-V level. The core
of the TMS320C6201 requires 2.5-V. All of the other DSPs in the TMS320C62x
and the TMS320C67x family need 1.8 V. The GTL bus, as well as various
processors and future DSPs, may require the 1.5-V controller. An external
resistor divider can be used to fine tune the output voltages of these controllers
for other applications including output voltages up to approximately
V
IN
– 0.5 V.
Table 1–1 summarizes the four EVM converter modules.
Table 1–1. Summary of EVM Converter Modules
EVM Part Number EVM Board
Number
Controller Output
Voltage
Max. Output
Current
TPS5633EVM–111 SLVP111 TPS5633 3.3 V 6 A †
TPS5625EVM–112 SLVP112 TPS5625 2.5 V 6 A †
TPS5618EVM–113 SLVP113 TPS5618 1.8 V 6 A †
TPS5615EVM–114 SLVP114 TPS5615 1.5 V 6 A †
† Output current is limited by the temperature rise of the power MOSFETs chosen. Higher or
lower current designs are possible .