Datasheet

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1 Background
The TPS55340 DC/DC Regulator is used typically in a boost topology, however this EVM demonstrates it
in a flyback topology. Rated input voltage and output current range for the evaluation module are given in
Table 1. This evaluation module demonstrates the performance of the TPS55340 in an example
application and can accommodate evaluation of other flyback applications supported by the TPS55340.
The switching frequency is externally set at a nominal 350kHz. The 40V, 5A, low-side MOSFET is
incorporated inside the TPS55340 package along with the gate-drive circuitry. The low drain-to-source on-
resistance of the MOSFET allows the TPS55340 to achieve high efficiencies. The compensation
components are external to the integrated circuit (IC). In this example application the absolute maximum
input voltage for the TPS55340EVM-148 is 24V.
Table 1. Input Voltage and Output Current Summary
EVM Input Voltage Range Maximum Output Current
TPS55340EVM-148 V
IN
= 8V to 24V, 12V nominal I
OUT
max = 2.5A
2 Performance Specification Summary
Table 2 provides a summary of the TPS55340EVM-148 performance specifications. The ambient
temperature is 25°C for all measurements, unless otherwise noted.
Table 2. Performance Specification Summary
Specification Test Conditions Min Typ Max Unit
V
IN
voltage range 8 12 24 V
No Load Input Current I
OUT
= 0A, V
IN
= 12V 6.3 mA
Output voltage set point 5 V
Line regulation I
OUT
= 2.5A, V
IN
= 8V to 24V ±0.1 %
Operating frequency 350 kHz
Output current range .001 2.5 A
Output over current limit
(1)
V
IN
= 8V 3.4 A
Output over current limit
(1)
V
IN
= 24V 4.8 A
Load regulation I
OUT
= 1mA to 2.5A, V
IN
= 8V to 24V ±0.1 %
Voltage change –140 mV
I
OUT
= 625mA to 1.875A, V
IN
= 12V
Recovery time 500 µs
Load transient response
Voltage change 60 mV
I
OUT
= 1.875mA to 625mA, V
IN
= 12V
Recovery time 500 µs
Loop bandwidth I
OUT
= 2.5A, V
IN
= 12V 7.8 kHz
Phase margin I
OUT
= 2.5A, V
IN
= 12V 56 °
Output ripple voltage I
OUT
= 2.5A, V
IN
= 12V 75 mVpp
Peak efficiency I
OUT
= 0.9A, V
IN
= 12V 87.9 %
Output current DCM threshold V
IN
= 12V 340 mA
(1)
The output over current limit is dependent on the input voltage and based on peak current limit of the TPS55340.
3 Modifications
These evaluation modules provide access to the features of the TPS55340 in a flyback topology.
Modifications to this module are possible to support other flyback applications.
3.1 Output Voltage Set Point
The resistor divider network of R8 and R14 sets the output voltage. Keep R14 fixed at or close to 10kΩ.
To change the output voltage of the EVM, change the value of resistor R8. Calculate the value of R8 for a
specific output voltage by using Equation 1 and the 1.24V V
REF
of U3. For output voltages greater than 6V,
it is recommended to use a TL431 for U3 with V
REF
= 2.495V and 36V maximum recommended output
voltage.
2
TPS55340EVM-148, 8V to 24V Input, 5V Output Flyback Evaluation Module SLVU751A–July 2012–Revised June 2013
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