TPS60241EVMĆ194 170 µVrms ZeroĆRipple Switched Cap BuckĆBoost Converter for VCO Supply User’s Guide November 2001 Power Management Products SLVU057
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 input voltage range of 2.7 V to 5.5 V with an output current up to 25 mA. 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.
Contents Contents 1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1 1.1 Basic Operation of the Device . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2 1.2 Family of Devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2 2 Demo Board Description . . . . . . . . . . . . . . .
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Chapter 1 Introduction The evaluation module (EVM) for the Texas Instruments (TI) TPS6024x charge pumps helps designers to evaluate these devices. With this board it is possible to evaluate the performance of the TPS60241. The layout of charge pumps is critical. The suggested layout of the demo board can be used as a reference design to reduce design time. Topic Page 1.1 Basic Operation of the Device . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2 1.2 Family of Devices . . . .
Basic Operation of the Device 1.1 Basic Operation of the Device The Texas Instruments TPS6024x 170 µVrms zero ripple switched capacitor buck-boost converters are intended for use with input voltages in the range of: - 1.8 V to 5.5 V for TPS60240, TPS60242, TPS60243 2.7 V to 5.5 V for TPS60241 A push-pull charge pump stage boosts the input voltage to the nominal output voltage, which is 5 V for the TPS60241. The minimum output current is 12 mA. With VIN > 2.95 V the maximum output current is 25 mA.
Chapter 2 Demo Board Description This chapter describes the circuit description, EVM layout, schematic, and EVM setup. Topic Page 2.1 Circuit Description and Schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2 2.2 Layout of the EVM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2 2.3 Setup of the EVM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Circuit Description and Schematic 2.1 Circuit Description and Schematic For all necessary signals there are single-pin connectors on the board. To operate the board, connect a power source with the appropriate voltage level between VIN and GND. Some additional GND-pins have been added for your convenience. C1 to C4 are 1206-size SMD-footprints. These parts are not necessary for operation and have only been added for test purposes.
Layout of the EVM Figure 2–2. Placement J1 EN C4 C6 IC1 ON C1 VIN GND_ C3 C2 GND VOUT OFF GND GND TPS60241EVM–194 SLVP194 The total space required for the IC and the capacitors on the EVM is only about 10 mm × 12 mm = 120 mm2. The capacitors are not optimized for space. They are optimized for performance. It is possible to use smaller capacitors to optimize the layout for minimum board space.
Setup of the EVM 2.3 Setup of the EVM For proper operation of the EVM, follow these steps: 1) Connect a load to the output (between VOUT and GND) with minimum R = 417 Ω, for VIN = 2.7 V to 5.5 V R = 200 Ω, for VIN = 2.95 V to 5.5 V 2) Connect a voltage source (or a battery pack) with the appropriate voltage between the input (VIN) and ground (GND): 2.7 V to 5.5 V.
Chapter 3 Capacitor Selection For the maximum output current and best performance, capacitors placed on the EVM are recommended. For lower currents or higher allowed output voltage ripple, other capacitors can also be used. It is recommended that the output capacitor has a minimum value of 0.22 µF. This value is necessary to assure a stable operation of the system. However, output ripple and noise are going to be much larger with such a low output capacitor.
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