SLVAFH4 January   2023 TPS62870 , TPS62870-Q1 , TPS62871 , TPS62871-Q1 , TPS62872 , TPS62872-Q1 , TPS62873 , TPS62873-Q1 , TPS62874-Q1 , TPS62875-Q1 , TPS62876-Q1 , TPS62877-Q1 , TPSM8287A06 , TPSM8287A10 , TPSM8287A12 , TPSM8287A15

 

  1.   Abstract
  2.   Trademarks
  3. 1Introduction
  4. 2Configurations
  5. 3Measurements
    1. 3.1 Efficiency
    2. 3.2 Input Voltage Ripple
    3. 3.3 Output Voltage Ripple
    4. 3.4 Load Transient
    5. 3.5 Heat Distribution
  6. 4Summary

2 Configurations

For the comparison in this application note, the TPS62873EVM-143 is used for the measurements at the single stage converter design and the TPS62873EVM-144 is used for the measurements at the dual converter design. Both circuits are configured to supply a 12-A load at 0.75 V. The circuits are also configured to support a fast load transient from 4.5 A to 12 A in 1 μs, allowing an output voltage deviation of less than 3.3%.

The TPS62873EVM-143 is already configured for this specification, so no modifications are needed for the measurements. The device was used with its default configuration. Figure 2-1 shows an overview of the critical components of the schematic and details of the BOM are listed in Table 2-1.

GUID-20221219-SS0I-7BVB-F0DJ-ZZDMW88VTG0K-low.png Figure 2-1 Single Converter Schematic
Table 2-1 Single Converter BOM
Ref Qty Value Description Size Part Number
CIN 2 0.47 µF Ceramic Capacitor, 10V, X7S 0402 GCM155C71A474KE36D
2 2.2 µF Ceramic Capacitor, 10V, X7S 0603 CGA3E3X7S1A225K080AB
2 10 µF Ceramic Capacitor, 10V, X7R 0805 GCM21BR71A106KE22
U1 1 2.7-V to 6-V Input, 12A, Fast Transient Synchronous Step-Down Converter with I2C Interface, Remote Sense and Stackability WQFN-FCRLF16 TPS62872QWRXSRQ1
L1 1 110 nH Inductor 4.0 × 4.0 × 2.0 mm XGL4020-111MEC
C1 1 1800 pF Ceramic Capacitor, 50V, X7R 0402
R1 1 2.43 kΩ Resistor 1%, 0.1 W 0402
C2 1 10pF Ceramic Capacitor, 50V, COG/NPO 0402
COUT 2 0.47 µF Ceramic Capacitor, 10V, X7S 0402 GCM155C71A474KE36D
2 22 µF Ceramic Capacitor, 10V, X7R 1206 GCM31CR71A226KE02
CLOAD 2 47 µF Ceramic Capacitor, 6.3V, X7R 1210 GCM32ER70J476ME19L
2 100 µF Ceramic Capacitor, 6.3V, X5R 1210 GRT32ER60J107ME13L
2 0.47 µF Ceramic Capacitor, 10V, X7S 0402 GCM155C71A474KE36D

The TPS62873EVM-144 by default is configured for an output current of 30 A. For the measurements for this application note the TPS62873 devices are changed to the lower current rated TPS62870 devices of the same device family. Since the current rating of the inductor can be lower as well a smaller inductor, the VCTA32252E-R11 was used to replace the larger XGL4020-110. With this modification the required PCB area for the two inductors in the stack is about the same as the required area for the single inductor in the single converter design. The amount of capacitors in the load side capacitor bank is also reduced from the default assembly which was designed to support higher output currents to the same configuration as it is used on the TPS62873EVM-143. Figure 2-2 shows an overview of the critical components of the dual converter schematic. Details of the BOM are listed in Table 2-2.

GUID-20221219-SS0I-19VD-GKCP-JJH1S9GCD57D-low.png Figure 2-2 Dual Converter Schematic
Table 2-2 Dual Converter BOM
Ref Qty Value Description Size Part Number
CIN1, CIN2 2 × 2 0.47 µF Ceramic Capacitor, 10V, X7S 0402 GCM155C71A474KE36D
2 × 2 2.2 µF Ceramic Capacitor, 10V, X7S 0603 CGA3E3X7S1A225K080AB
2 × 2 10 µF Ceramic Capacitor, 10V, X7R 0805 GCM21BR71A106KE22
U1,U2 2 × 1 2.7-V to 6-V Input, 6 A, Fast Transient Synchronous Step-Down Converter with I2C Interface, Remote Sense and Stackability WQFN-FCRLF16 TPS62870QWRXSRQ1
L1, L2 2 × 1 110 nH Inductor 3.2 × 3.2 × 2.5 mm VCTA32252E-R11
C1 1 6800 pF Ceramic Capacitor, 50V, X7R 0402
R1 1 820 Ω Resistor 1%, 0.1 W 0402
C2, C3 2 10 pF Ceramic Capacitor, 50 V, COG/NPO 0402
COUT1, COUT2 2 × 2 0.47 µF Ceramic Capacitor, 10 V, X7S 0402 GCM155C71A474KE36D
2 × 2 22 µF Ceramic Capacitor, 10 V, X7R 1206 GCM31CR71A226KE02
CLOAD 2 47 µF Ceramic Capacitor, 6.3V, X7R 1210 GCM32ER70J476ME19L
2 100 µF Ceramic Capacitor, 6.3 V, X5R 1210 GRT32ER60J107ME13L
2 0.47 µF Ceramic Capacitor, 10 V, X7S 0402 GCM155C71A474KE36D

More details of the test boards can be found in the EVM Users Guides for the TPS62873EVM-143 and TPS62873EVM-144.