User’s Guide March 2002 PMP Portable Power SLVU067
IMPORTANT NOTICE Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, modifications, enhancements, improvements, and other changes to its products and services at any time and to discontinue any product or service without notice. Customers should obtain the latest relevant information before placing orders and should verify that such information is current and complete.
EVM IMPORTANT NOTICE Texas Instruments (TI) provides the enclosed product(s) under the following conditions: This evaluation kit being sold by TI is intended for use for ENGINEERING DEVELOPMENT OR EVALUATION PURPOSES ONLY and is not considered by TI to be fit for commercial use.
EVM WARNINGS AND RESTRICTIONS It is important to operate this EVM within the specified input and output ranges described in the EVM User’s Guide. Exceeding the specified input range may cause unexpected operation and/or irreversible damage to the EVM. If there are questions concerning the input range, please contact a TI field representative prior to connecting the input power.
How to Use This Manual Preface About This Manual The TPS2151 is one of the four devices in the USB peripheral power management family TPS2140/41/50/51, which integrates both an adjustable linear low-drop voltage regulator (LDO) and a dual-current-limited power switch. The dual-current-limit power switch is designed to eliminate inrush current during power on.
Information About Cautions and Warnings Information About Cautions and Warnings This book may contain cautions and warnings. This is an example of a caution statement. A caution statement describes a situation that could potentially damage your software or equipment. This is an example of a warning statement. A warning statement describes a situation that could potentially cause harm to you. The information in a caution or a warning is provided for your protection.
Contents 1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1 2 Schematic, Bill of Materials, Layout, and Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1 Schematic of the EVM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2 Bill of Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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Chapter 1 Each device in TPS2140/41/50/51 family integrates a dual-current-limiting power switch and an adjustable low dropout regulator (LDO). Both the switch and LDO limit inrush current by controlling the turnon slew rate and are compatible with USB 1.0 and 2.0 Specifications. The power switch has a unique dual-current-limiting function that limits the current delivered to its load to less than 100 mA during power on.
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Chapter 2 This chapter contains schematics, bill of materials, board layout, and setup of EVM. Topic Page 2.1 Schematic of the EVM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2 2.2 Bill of Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4 2.3 Layout of the EVM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5 2.
Schematic of the EVM 2.1 Schematic of the EVM Figure 2–1 shows the schematic of the EVM. Figure 2–1.
Schematic of the EVM Only C2, C4, C5, C6, C8, R2, and R3 are essential for the TPS2151 to function properly. The rest of the components on the EVM are used for different evaluations of the device. To evaluate the power switch inrush current, a large capacitor C9 can be added on the EVM. In order to discharge SW_OUT and LDO_OUT quickly, JP4 and JP5 are shorted through jumpers on this EVM. Designers may unplug the jumpers and find the difference.
Bill of Materials Warning Users must not activate the load on SW_OUT before the SW_PG rises to high, if the load current is higher than 50 mA. Otherwise, the power switch output could not be charged up to SW_IN rail. 2.2 Bill of Materials The bill of materials (BOM) for the EVM is shown in Table 2–1. Table 2–1.
Layout of the EVM 2.3 Layout of the EVM Figure 2–2 illustrates the placement of the components on the top-layer of the TPS2151 EVM. All the components are placed on the top layer only. The bottom layer is mainly a ground plane except for a few short traces. The center rectangle box includes all the essential parts for the EVM. Figure 2–2.
Layout of the EVM 2.4 Setup of the EVM For proper operation of the EVM, please follow these steps for any evaluation: 1) Verify that the power supply voltages are in the required ranges: less than 5.5 V but higher than 4.1 V. Make sure the supplies have the capability to supply the current that the loads need. Turn off the supplies. 2) In order to discharge SW_OUT and LDO_OUT quickly, JP4 and JP5 are shorted through jumpers on this EVM. Designers may unplug the jumpers and find out the difference.
Chapter 3 C1, C2, C3, C4—input capacitors, at least 0.047µF total on each input. C5, C6, C8, C9—load capacitors, vary according to loads, but C5 plus C6 must be at least 4.7 µF. R2—top resistor of the resistor divider, refer to data sheet for its resistance value. R1—LDO_PG pullup resistor, must be at least 1kΩ. A total of 16 test points are provided.
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