User’s Guide TPS2350 −48-V Hot Swap/Supply Selector Evaluation Module User’s Guide 1
EVM IMPORTANT NOTICE (CATEGORY B) IMPORTANT: TI is providing the enclosed HPA021A evaluation module under the following conditions: This evaluation module (EVM) being provided by Texas Instruments (TI) is intended for use for ENGINEERING DEVELOPMENT OR EVALUATION PURPOSES ONLY and is not considered by Texas Instruments to be fit for commercial use.
DYNAMIC WARNINGS AND RESTRICTIONS It is important to operate this EVM within the maximum input voltage ranges specified in Table 2. 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. Applying loads outside of the specified output range may result in unintended operation and/or possible permanent damage to the EVM.
SLUU171A - September 2003 TPS2350 −48-V Hot Swap/Supply Selector Evaluation Module Portable Power Andy Ripanti ABSTRACT This User’s Guide describes the use and features of the TPS2350 −48-V Hot Swap/Supply Selector Evaluation Module (EVM). This EVM can be used to learn about the TPS2350 Hot Swap Power Manager (HSPM) Integrated Circuit (IC) from Texas Instruments (TI). Contents 1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
SLUU171A - September 2003 1 Introduction The TPS2350 is a negative voltage hot swap controller intended for use in systems needing to hot swap telecom distribution-level voltages. It integrates inrush current control, peak current limiting, electronic circuit breaker, and overvoltage and undervoltage protection. In addition, it monitors and selects from two power supplies the larger magnitude supply, reducing OR-ing losses in redundant supply systems.
SLUU171A - September 2003 2 The TPS2350 −48-V Hot Swap/Supply Selector EVM Kit 2.1 Module Description The TPS2350 −48-V hot swap/supply selector EVM kit is a PCB-based platform that enables designers to rapidly learn about the TPS2350 operation, and evaluate its performance during hot swap events. The assembly (TI part number HPA021−001) features a TPS2350 device as it may be connected in the power interface section of a hot swap-capable plug-in card.
SLUU171A - September 2003 The pictorial of the TPS2350 −48-V hot swap/supply selector EVM top assembly is shown in Figure 1. Figure 1.
SLUU171A - September 2003 2.2 EVM Schematic Diagram and List of Materials + + The EVM schematic diagram is shown in Figures 2 and 3. Figure 2.
SLUU171A - September 2003 Figure 3.
SLUU171A - September 2003 The EVM list of materials is shown in Table 1. Table 1. Evaluation Module List of Materials (HPA021A) DESCRIPTION MANUFACTURER PART NUMBER C1 REFERENCE 1 Capacitor, ceramic, 1000 pF, 25 V, 10%, X7R Vitramon VJ0805Y102KXXA C2 1 Capacitor, ceramic, 0.01 µF, 16 V, 10%, X7R Vitramon VJ0805Y103KXJA C3 1 Capacitor, ceramic, 0.047 µF, 16 V, 10%, X7R Vitramon VJ0805Y473KXJA C4 1 Capacitor, ceramic, 0.
SLUU171A - September 2003 2.3 TPS2350 −48-V Hot Swap/Supply Selector EVM Operating Specifications The supply selector EVM is intended to allow some degree of user reconfiguration. This allows designers to set up the circuit to better represent the characteristics of their target application. Potential modifications include changing the current limit threshold, the inrush limiting, the fault timing, and load characteristics.
SLUU171A - September 2003 3.2 Verifying the EVM Operation The following procedure steps may be used to verify functional operation of the EVM after receipt. 3.2.1 Equipment Setup On the EVM, place the POWER and ENABLE switches in the OFF position. Set the DIP switches 1 through 4 of switch SW1 to the ON position. Turn on power supply number 1 (PS No. 1) and adjust the output for about 48 V. Turn on power supply number 2 (PS No. 2) and adjust the output for about 44 V.
SLUU171A - September 2003 3.2.2 Functional Test Turn on all the power supplies. On the EVM, place the POWER switch in the ON position. Verify the FAULT LED (D1) remains off. Verify the voltage readings in Table 4 are obtained at the corresponding test points. Table 4. Test Point Voltages −− Outputs OFF TEST POINT REFERENCE VOLTAGE READING TP22 TP24/TP25 0 ± 200 mV J7 TP24/TP25 250 mV max. Place the ENABLE switch in the ON position. Verify the FAULT LED (D1) remains off.
SLUU171A - September 2003 4 Using the EVM Kit to Evaluate the TPS2350 Procedures similar to the steps of Section 3.2.2 for functional test of the EVM can also be used to continue evaluation of the TPS2350 hot swap controller device. Additional details about the EVM features are provided in this section. 4.1 Supply Connections and Test Points Supply connections to the EVM should be made to the banana jacks as shown in Figure 4. The two backplane, 48-V supplies (PS No. 1 and PS No.
SLUU171A - September 2003 4.2 Load Capacitors Capacitor patterns C8 and C9 are available on the EVM for installation of components to represent the module input bulk capacitance; i.e., the load capacitance seen by the hot swap interface circuit. As supplied from the factory, the EVM contains a 100-µF aluminum electrolytic installed at C8. Further customization to approximate the user’s application can be done using either C8 or C9.
SLUU171A - September 2003 In the Figure 6 plot, the TPS2350 is switchng from the A supply to the B supply when the initially higher-potential A supply lead is rapidly pulled from the input jack. At the time the lead is disconnected, current from that source is interrupted. The bulk capacitor holds up the sense node voltage momentarily (seen here on the VOUT+ trace); however, the 1-A load eventually causes it to decay below the magnitude of the B supply, which was 40 V.
SLUU171A - September 2003 The EVM can be used to get an illustration of the relationship between current limit, inrush slew rate, load values, and the circuit’s fault timing requirements. With DIP switch SW1−1 only closed, the fastest of the preset slew rates is selected, and only the hard-wired timing capacitor C6 is connected to the TPS2350 controller. However, this is sufficient to allow the bulk capacitor C8 to fully charge, from 0 V, across the full range of input supply voltages, down to −80 V.
SLUU171A - September 2003 4.6 Fault Timing with the TPS2350 Whenever the hot swap controller is limiting current to the load, an on-chip timer is monitoring this operation against an established time limit. The timeout period is generated by the constant-current charging of a capacitor at the FLTTIM pin. If current regulation ceases prior to expiration of the timer, the capacitor is discharged, and normal steady-state operation of the load either starts or resumes.
SLUU171A - September 2003 The thresholds are easily modified by changing the resistor values. When the desired trip voltages and the UV hysteresis have been established for the protected load, new values are determined as follows. Generally, the process is simplest by first selecting the top leg of the divider (R1) needed to obtain the desired hysteresis. This value is calculated from equation 4. R1 + V HYS_UV 10 mA (4) where VHYS_UV is the desired amount of undervoltage hysteresis.
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