TPS62737EVM-560

User's Guide SLVU939A – July 2013 – Revised August 2014 Evaluation Module for TPS62737 Ultra Low Power Buck Converter This user’s guide describes the TPS62737 evaluation module (EVM). The TPS62737 device is a highfrequency synchronous stepdown dc-dc converter optimized for ultralow-power energy harvesting applications. The converter can provide up to 2900 mA of continuous current to a 1.3- to 5.3-V output from input voltages up to 5.5 V. 1 2 3 4 Contents Introduction ................................................................................................................... 1.1 TPS62737 IC Features............................................................................................. 1.2 TPS62737EVM Features .......................................................................................... 1.3 TPS62737EVM Schematic ........................................................................................ Performance Specification Summary ..................................................................................... Test Summary ................................................................................................................ 3.1 Recommended Equipment ........................................................................................ 3.2 Equipment and EVM Setup........................................................................................ 3.3 Tips when Measuring Efficiency .................................................................................. 3.4 Tips for Taking Scope Plots ....................................................................................... 3.5 Test Results ......................................................................................................... PWR560 PCB Layout and Bill of Materials ............................................................................... 4.1 REV A PCB Layout ................................................................................................. 4.2 Bill of Materials ...................................................................................................... 2 2 2 3 4 4 4 4 5 5 6 8 8 9 List of Figures ........................................................................................ ............................................................................... Ship-Mode Startup Behavior, VIN = 3.6V, VOUT = 1.8V .................................................................. Standby Mode Startup Behavior, VIN = 3.6V, VOUT = 1.8V .............................................................. Load Transient Response, VIN = 3.6 V, VOUT=1.8V ...................................................................... Steady State Operation, VIN = 3.6V, V OUT = 1.8V, ROUT= 9 Ω ........................................................... Top Layer ..................................................................................................................... Bottom Layer ................................................................................................................. 1 TPS62737 EVM Board Schematic 3 2 EVM Test Setup for Measuring Efficiency 5 3 4 5 6 7 8 SLVU939A – July 2013 – Revised August 2014 Submit Documentation Feedback Evaluation Module for TPS62737 Ultra Low Power Buck Converter Copyright © 2013–2014, Texas Instruments Incorporated 6 6 7 7 8 8 1 Introduction 1 Introduction 1.1 TPS62737 IC Features www.ti.com The TPS62737 is a highly integrated ultra low power buck converter solution that is well suited for meeting the special needs of ultra low power applications such as energy harvesting. The TPS62737 provides the system with an externally programmable regulated supply in order to preserve the overall efficiency of the power management stage versus a linear step down converter. Although intended to have input power from an energy storage element such as a Li-Ion battery or super cap, the TPS62737 can accept any input voltage up to 5.5 V, while supplying the rail to low voltage electronics. The TPS62737 integrates an optimized hysteretic controller for low power applications. The internal circuitry utilizes a time based sampling system in order to reduce the average quiescent current. This allows for the quiescent current consumption to scale with output load levels. The regulated output has been optimized to provide high efficiency across low output currents (< 10 µA) to high currents (200 mA). To further assist users in the strict management of their energy budgets, the TPS62737 toggles the input good (VIN_OK) flag to signal an attached microprocessor when the voltage on the input supply has dropped below a pre-set critical level. The intent of VIN_OK is to trigger the reduction of load currents to prevent the system from entering an undervoltage condition. Two separate enable signals allow the user to enable/disable the regulated output or place IC into an ultra-low quiescent sleep state. Two separate enable signals allow the enabling or disabling of the regulated output or allow putting the IC into an ultralow quiescent sleep state. The output voltage regulation point and input good threshold are set by external resistors. In order to maximize efficiency at light load, the use of voltage level setting resistors > 1 MΩ is recommended. However, during board assembly or modification, contaminants such as solder flux and even some board cleaning agents can leave residue that may form parasitic resistors across the physical resistors and/or from one end of a resistor to ground, especially in humid, fast airflow environments. This can result in the voltage regulation and threshold levels changing significantly from those expected per the installed resistor values. Therefore, the boards must be carefully cleaned then rinsed with de-ionized water until the ionic contamination of that water. If this is not feasible, then it is recommended that the sum of the voltage setting resistors be reduced. 1.2 TPS62737EVM Features 1. 2. 3. 4. 5. 2 Input voltage range from 2.0 V to 5.5 V Output voltage set to 1.8 V but adjustable from 1.3 V to 5.3 V with external resistors VIN_OK threshold of 2.9 V but adjustable from VOUT to 5.3 V with external resistors Easily accessible headers for IN, IN-SENSE, OUT, OUT-SENSE, GND, VIN_OK Jumpers for EN1 and EN2 Evaluation Module for TPS62737 Ultra Low Power Buck Converter Copyright © 2013–2014, Texas Instruments Incorporated SLVU939A – July 2013 – Revised August 2014 Submit Documentation Feedback Introduction www.ti.com 1.3 TPS62737EVM Schematic J1 1 IN 2 2.0V-5.5V, 400mA VIN J2 VIN 1 L1 C1 C2 AGND 1 VIN_OK 22 uF 1 0.1uF 1 10 5 6 7 2 VIN_OK EN1 EN2 VRDIV SW SW OUT NC NC 2 13 1 2 J4 10 uH 2 11 OUT C3 1 1.3V-5.5V, 200mA C4 4 14 22uF 1 GND IN 9 AGND 8 AGND VOUT_SET VIN_OK_SET VSS VSS PAD 3 12 1 J3 1 2 GND-SNS 2 2 U1 2 2 IN-SNS AGND TPS62737RGY VIN AGND 3 LO OUT-SNS 1 GND-SNS AGND 2 EN1 2 AGND 1 HI J5 J6 R3 4.32M JP1 2 GND 1 AGND R2 AGND VIN J7 2 VIN_OK R1 JP2 2 3 1 EN2 LO 3.4M 1 HI 2 VIN_OK 1 GND 5.49M AGND AGND AGND Figure 1. TPS62737 EVM Board Schematic SLVU939A – July 2013 – Revised August 2014 Submit Documentation Feedback Evaluation Module for TPS62737 Ultra Low Power Buck Converter Copyright © 2013–2014, Texas Instruments Incorporated 3 Performance Specification Summary 2 www.ti.com Performance Specification Summary Specification Conditions MIN Input dc voltage, IN MAX 5.5 UNIT V Output dc voltage, OUT Adjustable by changing external resistors from 1.3 V to 5.3 V 1.8 V VBAT_OK threshold Adjustable by changing external resistors from OUT to 5.3 V 2.9 V Output current 0 3 Test Summary 3.1 Recommended Equipment • • • • • 3.2 TYP 2.0 200 mA Adjustable dc power supply between 2.0 V and 5.5 V with the adjustable current limit set to approximately 400 mA Load: system load or resistive load ≥ 9 Ω Two digital multimeters configured to measure voltage (equivalent or better) Two digital multimeters configured to measure current (equivalent or better). NOTE: Due to the input current pulses inherent to a hysteretically-controlled converter, the input current meter must be capable of filtering and/or averaging in order to measure the correct value. Adding a large (> 100 µF) capacitor between IN and GND may be used to assist with filtering; however, such capacitors tend to have high leakage currents that may artificially increase quiescent current measurements at no load. Use of a sourcemeter, configured to regulate voltage and measure current, or power, or both current and power is also recommended when taking efficiency measurements. Oscilloscope with up to four voltage probes Equipment and EVM Setup Table 1. Setup I/O Connections and Configuration for Measuring Efficiency of TPS62737 EVM Jack and Component (Silk Screen) Description Connect or Adjustment To: J1 (IN) Negative lead of current meter (CM#1) J2-1 (+ IN SNS) Kelvin connection to capacitance Positive lead of voltmeter (VM#1) J2-2 (- GND SNS) Kelvin connection to capacitance Negative lead of voltmeter (VM#1) J3 (GND) Power supply negative lead J4 (OUT) Positive lead of current meter (CM#2) J5-1 (+ OUT SNS) Kelvin connection to capacitance Positive lead of voltmeter (VM#2) J5-2 (- GND SNS) Kelvin connection to capacitance Negative lead of voltmeter (VM#2) J6 (GND) J7-1 (VIN_OK) Negative lead to load resistance Push-pull output of comparator that indicates the status of the input voltage J7-2 (GND) 4 n/a n/a JP1 (EN1) EN1 = HI and EN2 = x implements full standby mode. Switching converter and VIN_OK indication is off (ship mode). EN1 = LO JP2 (EN2) EN1 = LO and EN2 = HI implements full buck converter mode. EN1 = LO and EN2 = LO implements partial standby mode. Switching converter is off, but VIN_OK indication is on. EN2 = HI Evaluation Module for TPS62737 Ultra Low Power Buck Converter Copyright © 2013–2014, Texas Instruments Incorporated SLVU939A – July 2013 – Revised August 2014 Submit Documentation Feedback Test Summary www.ti.com Table 1 and Figure 2 show the test setup for measuring efficiency. CM #1