Texas Instruments TPS53681EVM-002 User Manual

SLUUBP7–December 2017

Using the TPS53681EVM-002, Dual Multiphase DC-DC

Step-Down Analog Controller with PMBus™ Interface

This User Guide describes the evaluation module (EVM) for the TPS53681 analog power controller, a driverless D-CAP+™ multiphase buck controller, which manages several high current phases of the CSD95490, a NexFet™ Smart Synchronous Buck Power Stage.

Contents

1 Description.................................................................................................................... 1

2 Typical Applications ......................................................................................................... 2

2.1 Features.............................................................................................................. 2

3 Electrical Performance Specifications..................................................................................... 3

4 Schematic..................................................................................................................... 4

5 Test Setup................................................................................................................... 12

5.1 Test and Configuration Software ................................................................................ 12

5.2 Test Equipment.................................................................................................... 12

5.3 Recommended Test Setup....................................................................................... 13

6 EVM Configuration Using the Fusion GUI .............................................................................. 14

6.1 Configuration Procedure ......................................................................................... 14

7 Test Procedure ............................................................................................................. 14

7.1 Line/Load Regulation and Efficiency Measurement Procedure............................................. 14

7.2 High Current Operation........................................................................................... 15

7.3 Multiphase/Multi-rail Configurations............................................................................. 16

7.4 On-Board Transient Load Operation............................................................................ 16

7.5 Efficiency ........................................................................................................... 17

7.6 Equipment Turn-on and Shutdown.............................................................................. 18

8 Performance Data and Typical Characteristic Curves................................................................. 19

9 EVM Assembly Drawing .................................................................................................. 24

10 Bill of Materials ............................................................................................................. 26

11 Fusion GUI .................................................................................................................. 30

1 Description

The TPS53681EVM implements a typical application for a low-voltage, high current dual output power converter, operating from a nominal 12-V input rail to produce a 0.9-V output rail at up to 294 A of load current and a 0.8-V rail at up to 47 A. The EVM includes test points for evaluating the performance of the TPS53681 controller and CSD95490 power stages.

For ease of evaluation, the EVM requires only one (12-V) input supply and an output load to get started with testing, however the user can opt to independently provide 5-V for greater control over the Power Stage voltage. With the addition of the Fusion Digital Power™ Designer software, the EVM’s PMBus™ interface allows access to the controller NVM for evaluation of additional configuration, control and monitoring possibilities. Refer to the TPS53681 datasheet (SLUSCT1) for complete information on configuring multi-phase operation with this controller.

SLUUBP7–December 2017

Submit Documentation Feedback

Using the TPS53681EVM-002, Dual Multiphase DC-DC Step-Down Analog

Controller with PMBus™ Interface

Typical Applications

2 Typical Applications

• High current ASIC and FPGA core power in the following equipment:

– Wired and Wireless Networking – Enterprise Server and Storage Networks – Test & Measurement – Smart Grid Infrastructure – Aerospace and Defense – Merchant Power Supplies

2.1 Features

• Dual regulated high current outputs

• Programmable settings available through PMBus™ interface

– Output voltage trim – Output voltage margin levels (High / Low) within a maximum range – UVLO protection threshold – Soft-start slew-rate – Device enable and disable – Overcurrent warning and fault limits – SW frequency – BOOT voltage – Monitoring of input & output voltage, current, power, and power stage temperature

• Convenient test points for probing critical waveforms

www.ti.com

Using the TPS53681EVM-002, Dual Multiphase DC-DC Step-Down Analog Controller with PMBus™ Interface

SLUUBP7–December 2017

Submit Documentation Feedback

www.ti.com

3 Electrical Performance Specifications

Table 1. TPS53681EVM Electrical Performance Specifications

PARAMETER TEST CONDITIONS MIN TYP MAX UNITS

INPUT CHARACTERISTICS

IN(max)

OUTPUT CHARACTERISTICS

OUT

RIPPLE

SYSTEMS CHARACTERISTICS

Voltage range 10 12 14 V Maximum input current

VIN= 12 V, I 47 A

VIN= 12 V, I

No load input current

A, Dynamic Phase Shedding disabled

Output voltage

Output load current

Output voltage load regulation

Output voltage ripple

Output overcurrent protection (OCP)

RAIL A 0.9 V RAIL B 0.8 V RAIL A (6-phase mode) 0 294 A RAIL B (2-phase mode) 0 47 A 0 A ≤ I 0 A ≤ I VIN= 12 V, I VIN= 12 V, I

RAIL A 382.5 A

Rail A Switching frequency VIN= 12 V 500 kHz Rail A Peak efficiency VIN= 12 V, I Rail A Full-load efficiency VIN= 12 V, I Rail B Switching frequency VIN= 12 V 500 kHz Rail B Peak efficiency VIN= 12 V, I Rail B Full-load efficiency VIN= 12 V, I Operating temperature 25 ºC

Electrical Performance Specifications

= 294 A, I

OUTA

= 0 A, I

OUTA

≤ 294 A 0.15%

OUTA

≤ 47 A 0.15%

OUTB

= 150 A 4 mVpp

OUTA

= 45 A 5 mVpp

OUTB

= 90 A 93.0%

OUTA

= 294 A 87.5%

OUTA

= 25 A 91.8%

OUTB

= 47 A 90.6%

OUTB

= 0

30 A

330 mA

SLUUBP7–December 2017

Submit Documentation Feedback

Using the TPS53681EVM-002, Dual Multiphase DC-DC Step-Down Analog

Controller with PMBus™ Interface

Schematic

www.ti.com

SLUUBP7–December 2017

Submit Documentation Feedback

Using the TPS53681EVM-002, Dual Multiphase DC-DC Step-Down Analog Controller with PMBus™ Interface

4 Schematic

Figure 1. TPS53681EVM - Controller Schematic

www.ti.com

Schematic

SLUUBP7–December 2017

Submit Documentation Feedback

Using the TPS53681EVM-002, Dual Multiphase DC-DC Step-Down Analog

Controller with PMBus™ Interface

Figure 2. TPS53681EVM - Rail A Power Stages 1-3-5 Schematic

Schematic

www.ti.com

SLUUBP7–December 2017

Submit Documentation Feedback

Using the TPS53681EVM-002, Dual Multiphase DC-DC Step-Down Analog Controller with PMBus™ Interface

Figure 3. TPS53681EVM - Rail A Power Stages 2-4-6 Schematic

www.ti.com

Schematic

SLUUBP7–December 2017

Submit Documentation Feedback

Using the TPS53681EVM-002, Dual Multiphase DC-DC Step-Down Analog

Controller with PMBus™ Interface

Figure 4. TPS53681EVM - Rail B Power Stages Schematic

Schematic

www.ti.com

SLUUBP7–December 2017

Submit Documentation Feedback

Using the TPS53681EVM-002, Dual Multiphase DC-DC Step-Down Analog Controller with PMBus™ Interface

Figure 5. TPS53681EVM - AUX Voltages Schematic

www.ti.com

Schematic

SLUUBP7–December 2017

Submit Documentation Feedback

Using the TPS53681EVM-002, Dual Multiphase DC-DC Step-Down Analog

Controller with PMBus™ Interface

Figure 6. TPS53681EVM - Helper Circuits and Indicators Schematic

Schematic

www.ti.com

SLUUBP7–December 2017

Submit Documentation Feedback

Using the TPS53681EVM-002, Dual Multiphase DC-DC Step-Down Analog Controller with PMBus™ Interface

Figure 7. TPS53681EVM - Input and Output Filter Schematic

www.ti.com

Schematic

SLUUBP7–December 2017

Submit Documentation Feedback

Using the TPS53681EVM-002, Dual Multiphase DC-DC Step-Down Analog

Controller with PMBus™ Interface

Figure 8. TPS53681EVM - On Board Transient Load Schematic

Test Setup

5 Test Setup

5.1 Test and Configuration Software

The Texas Instruments Fusion Digital Power Designer software can expand the functionality of the EVM. To download this software, visit the Fusion Digital Power Software page.

5.1.1 Description

The Fusion Digital Power Designer is a graphical user interface (GUI) used to configure, control and monitor the TPS53681 controller on the EVM. The software uses the PMBus™ protocol to communicate with the controller over a serial bus by way of the TI USB-to-GPIO Adapter.

5.1.2 TI Fusion Digital Power Designer Features

The software offers these features:

• Turn on or off the power supply output, either through the hardware control line or the PMBus™

Operation command.

• Monitor real-time data. Items such as input voltage, input current, output voltage, output current,

temperature, warnings and faults are continuously monitored and displayed by the GUI.

• Configure common operating characteristics such as output voltage trim and margin, VINUVLO, soft-

start slew rate, switching frequency, and warning and fault thresholds.

5.2 Test Equipment

www.ti.com

5.2.1 Voltage Sources

Only one DC input voltage sources is needed (VIN). The VIN input voltage source should be a 0 V to 14 V variable DC source capable of supplying 40 Adc. Connect VIN to terminals J6 and J7 as shown in

Figure 9.

For greater control during testing, one can remove jumpers from J2 and J4 to bypass the onboard 5-V power supply. This external supply should be limited to 1 Adc.

5.2.2 Multimeters

It is recommended to use two separate multimeters, one meter to measure VINand the other to measure V

OUT

5.2.3 Output Load

An electronic load is recommended for the test setup shown in Figure 9. To observe the Rail A at full load the electronic load should be capable of sinking 294 A at 0.9-V (Rail B, 47 A at 0.8-V).

5.2.4 Oscilloscope

Use an oscilloscope to measure output noise and ripple. Use a coaxial cable to measure output ripple across the output ceramic capacitors.

5.2.5 Fan

During prolonged operation at high load (More than 100 A), it is necessary to provide forced air cooling with a small fan aimed at the EVM. Maintain the temperature of the devices on the EVM under 115°C.

5.2.6 USB-to-GPIO Interface Adapter

A communications adapter is required between the EVM and the host computer. This EVM is designed to use the Texas Instruments USB-to-GPIO adapter connected to J12. To purchase this adapter visit the TI

USB-to_GPIO tool page.

Using the TPS53681EVM-002, Dual Multiphase DC-DC Step-Down Analog Controller with PMBus™ Interface

SLUUBP7–December 2017

Submit Documentation Feedback

GND

12VIN

VOUTA+

VOUTB+

GND

5VIN*

GND

*IF EXTERNAL

SOURCE IS USED

www.ti.com

5.2.7 Recommended Wire Gauge

VOLTAGE (V) CONNECT

12 VIN to J6, GND to J7 2 x AWG #8

5 (if J2 open) 5VIN to J1 2 x AWG #18 2 n/a

0.9

0.8

(1)

Total length of wire less than 4 feet (2 feet input or output, 2 feet return).

Load+ to T1, T2, and T3,

Load- to T4, T5, and T6

Load+ to T7 and T8, Load- to T9 and T10

5.3 Recommended Test Setup

Figure 9 shows the recommended test setup, which includes VIN input voltage source(s) and output load.

Table 2. Recommended Wire Gauge

RECOMMENDED

WIRE SIZE

6 × AWG #4 n/a 2

4 × AWG #8 n/a 2

MAXIMUM TOTAL WIRE LENGTH

RETURN INPUT OUTPUT

Test Setup

(1)

(FEET)

2 n/a

Figure 9. TPS53681EVM Recommended Test Setup

SLUUBP7–December 2017

Submit Documentation Feedback

Using the TPS53681EVM-002, Dual Multiphase DC-DC Step-Down Analog

Controller with PMBus™ Interface

EVM Configuration Using the Fusion GUI

6 EVM Configuration Using the Fusion GUI

The controller on this EVM leaves the factory pre-configured. Table 3 lists some key factory configuration parameters from the configuration file.

Table 3. Key Factory Configuration Parameters

www.ti.com

CMD NAME PMBus

VIN_ON 0x35 0xF029 10.25 V Input voltage turn on threshold Rail A IOUT_OC_FAULT_LIMIT 0x46 0x017E 382.00 A Rail A OC fault level Rail A IOUT_OC_WARN_LIMIT 0x4A 0x00FF 255.0 A Rail A OC warning level Rail B IOUT_OC_FAULT_LIMIT 0x46 0x005A 135.00 A Rail B OC fault level Rail B IOUT_OC_WARN_LIMIT 0x4A 0x0087 90.0 A Rail BOC warning level ON_OFF_CONFIG 0x02 0x17 Control Pin only Power is converted when the control

OT_FAULT_LIMIT 0x4F 0x0073 115 °C OT fault level OT_WARN_LIMIT 0x51 0x0069 105 °C OT warning level Rail A Max Num Phases 0xE4 0x05 6 Phase Rail number of phases FSW 0x33 0x01F4 500kHz Switching frequency Rail A VBOOT 0xDB 0x83 0.900V Rail A VBOOT voltage Rail B VBOOT 0xDB 0x6F 0.800V Rail B VBOOT voltage

To configure the EVM with other than the factory settings shown in Table 3, use the TI Fusion Digital Power Designer software for reconfiguration. Be sure to apply input voltage to the EVM prior to launching the software. This sequence ensures that the controller and GUI recognize each other.

6.1 Configuration Procedure

1. Connect USB-to-GPIO adaptor to J12.

2. Apply the input power source VIN to the EVM. Refer to Figure 9.

3. Ensure that the controller is receiving 3.3-V (either through the onboard LDOs or an external supply)

4. Launch the Fusion GUI software.

5. Configure the EVM operating parameters as desired.

COMMAND CODE

HEX VALUE PHYSICAL

SETTING

COMMENTS

pin is active

7 Test Procedure

7.1 Line/Load Regulation and Efficiency Measurement Procedure

1. Set up EVM as shown in Figure 9.

2. Ensure the electronic load is set to draw 0 Adc.

3. Check to see if jumpers are in desired configuration (Refer to Table 4)

4. Increase VIN from 0-V to 12-V.

5. Change the relevant switch to ON position (S1 for Rail A, S2 for Rail B).

6. Turn on the external fan if necessary (When driving a load above 50A).

7. Vary the load from 0 Adc to 294 Adc for Rail A (0 Adc to 47 Adc for Rail B) Ensure V

regulation as defined in Table 1.

8. Vary VIN from 10-V to 14-V. Ensure V

9. Decrease the load to 0 A.

10. Change relevant switch to OFF position (S1 for Rail A, S2 for Rail B).

11. Decrease VIN to 0 V.

12. Shut down the external fan if in use.

Using the TPS53681EVM-002, Dual Multiphase DC-DC Step-Down Analog Controller with PMBus™ Interface

remains in regulation as defined in Table 1.

OUT

remains in

OUT

SLUUBP7–December 2017

Submit Documentation Feedback

+ 31 hidden pages

Texas Instruments TPS53681EVM-002 User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual