LM5152EVM-BST Evaluation Module
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1 Introduction
The LM5152EVM-BST evaluation module is designed to evaluate the operation and performance of the LM5152-Q1 low-IQ synchronous boost controller. The EVM operates over an input voltage range of 2.5 V to 36 V and requires minimum of 7-V input to start up. The EVM provides a 8.5-V output with a maximum load current of 4 A at 2.5-V input or 6 A at 4.5-V input. Figure 1-1 shows the standard application circuit for the LM5152EVM-BST evaluation module.
Figure 1-1 Typical Application Circuit1.1 Applications
- Automotive start-stop application
- Automotive backup power supply application
1.2 Features
The LM5152EVM-BST has the following features:
- Input voltage range from 2.5 V to 36 V (7 V to start up)
- Internal low leakage current high-impedance feedback resistors with programmable output voltage
- Operating frequency of 440 kHz with externally clock synchronization up or down by 20%
- Bypass mode operation when VIN is greater than VOUT
- Selectable forced PWM (FPWM), skip mode, or diode emulation using the MODE pin
- High power conversion efficiency across a wide operating range
- Cycle-by-cycle peak current limiting
- Optional frequency dithering for improved EMI performance
- Boost STATUS indicator
- Programmable soft-start time
- Programmable line undervoltage lockout (UVLO)
2 EVM Setup
Section 2 describes the operating conditions for the EVM, as well as the configuration points of the evaluation module.
Figure 2-1 EVM Photo
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| Prolonged operation with low
input voltage at full power will cause heating of Q1, Q4, L2, and R3. Board surface is hot. Do not touch! Contact may cause burns. |
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2.1 EVM Characteristics
Table 2-1 details the EVM characteristics.
| PARAMETER | TEST CONDITION | MIN | TYP | MAX | UNIT |
|---|---|---|---|---|---|
| Input voltage range | Operation | 2.5 | 13.5 | 36 | V |
| Start-up voltage | 7 | V | |||
| Input current | 17 | A | |||
| Output voltage | 8.5 | V | |||
| Output current1 | 2.5 V ≤ VSUPPLY < 4.5 V | 4 | A | ||
| Output current2 | 4.5 V ≤ VSUPPLY < 36 V | 6 | A | ||
| Switching frequency | 440 | kHz |
2.2 EVM Connectors and Test Points
Section 2 describes the connection points of the evaluation module. Table 2-2 to Table 2-4 describe these connections. Table 2-2 lists the power connections of the evaluation module. These connections are intended to handle relatively large currents.
| JUMPER | PIN | DESCRIPTION |
|---|---|---|
| J1 | VIN+ | Positive input voltage power for the evaluation module |
| J2 | VOUT+ | Positive output voltage power for the evaluation module |
| J4 | GND | Negative output voltage power for the evaluation module |
| J5 | VIN– | Negative input voltage power for the evaluation module |
Table 2-3 lists the EVM jumpers and test points that configure the LM5152-Q1 as desired. These jumpers can set different modes of operation or provide signals to different pins of the LM5152-Q1.
| JUMPER | PINS | DESCRIPTION | DEFAULT CONNECTION |
|---|---|---|---|
| J7 | Pin 1 to Pin 2 | SYNC/DITHER/VH/CP is pulled to VCC through a 1-kΩ resistor to enable the internal charge pump or enable the VCC holdup functionality. This connection must not be made if the J10 is populated. | |
| Pin 2 to Pin 3 | SYNC/DITHER/VH/CP is pulled to AGND through a 1-kΩ resistor to disable the internal charge-pump and VCC holdup functionality. | ||
| Open | If an external clock synchronization on J10 is used, leave this jumper open. | X | |
| J9 | VTRK_D | PWM signal applied through a two stage low-pass filters to the TRK pin. R17 must be populated. | |
| J10 | Pin 1 to Pin 2 | SYNC/DITHER/VH/CP pulled to ground, disabling dithering, internal charge-pump functionality, and VCC holdup functionality. J10 must not be populated when J7 is populated between pin 1 and pin 2. | X |
| Open | Dithering is enabled. To synchronize to an external clock, remove C37. | ||
| J11 | Pin 1 to Pin 2 | Bypass D1 to tie either VIN or VOUT nets to the BIAS pin. | X |
| Open | Either VIN or VOUT is supplied through D1 to the BIAS pin. | ||
| J12 | Pin 1 to Pin 2 | VIN is supplied to the BIAS pin. This is the default connection. | X |
| Pin 2 to Pin 3 | VOUT is supplied to the BIAS pin. | ||
| J13 | Pin 1 to Pin 2 | Connect an auxiliary power supply that can be used to supply power to the BIAS pin. J11 must be open if this is populated. | |
| Pin 2 to Pin 3 | Connect VCC to BIAS. | ||
| Open | X | ||
| J14 | Pin 1 to Pin 2 | Configures light-load switching operation to be FPWM | X |
| Pin 2 to Pin 3 | Configures light-load switching operation to be diode emulation | ||
| Open | Configures light-load switching operation to be skip | ||
| TP6 | Positive input to the VAUX net | ||
| TP7 | Negative input to the VAUX net | ||
| TP8 | Positive input to the TRK pin | ||
| TP9 | Negative input to the TRK pin |
Table 2-4 indicates the dedicated voltage probe points of the EVM. These points are used to make measurements on the EVM.
| SENSE POINT | NAME | DESCRIPTION |
|---|---|---|
| TP1 | VIN+ | Sense point for the positive input voltage |
| TP2 | VOUT+ | Sense point for the positive output voltage |
| TP3 | SW | Sense point for the switch node of the boost controller |
| TP4 | GND | Sense point for the negative output voltage |
| TP5 | VIN– | Sense point for the negative input voltage |
| J3 | PGND | Power ground connection |
| J6 | PGND | Power ground connection |
| J8 | 1 | BIAS |
| 2 | VCC | |
| 3 | STATUS | |
| 4 | UVLO | |
| 5 | COMP | |
| 6 | SS | |
| 7 | AGND |
3 Test Setup and Procedures
Figure 3-1 shows the required test setup to recreate the results found in Section 4.
Figure 3-1 EVM Test Setup3.1 Equipment
The following test equipment is needed to test the LM5152EVM-BST as shown in Figure 3-1.
- Power supply: The input voltage source
(VIN) must be a variable supply with minimum efficiency level V.
The power supply must source 2.5 V to 36 V and be able to supply more than 20 A
of current. TI recommends using an external power supply that complies with
applicable regional safety standards such as (by example) the following:
- UL
- CSA
- VDE
- PSE
- Electronic load: Load connected to the output of the evaluation module. The electronic load must be able to handle up to 36 V and dissipate 100 W at 8.5 V.
- Multimeters: For DC measurements
- Voltmeter 1 (VIN): Capable of measuring the input voltage range up to 36 V
- Voltmeter 2 (VOUT): Capable of measuring output voltage of 36 V
- Ammeter 1 (IIN): Capable of 20-A DC measurement. A shunt resistor can also be used to measure the input current.
- Ammeter 2 (IOUT): Capable of at least 6-A DC measurement
- Oscilloscope: Minimum of 20-MHz bandwidth and 10x probes
4 Test Results
Section 4 covers the test results of the evaluation module.