ZHCSOH8F July 2021 – August 2024 TPS7H5001-SP , TPS7H5002-SP , TPS7H5003-SP , TPS7H5004-SP
PRODUCTION DATA
- 1
- 1 特性
- 2 应用
- 3 说明
- 4 Device Comparison Table
- 5 Device Options
- 6 Pin Configuration and Functions
-
7 Specifications
- 7.1 Absolute Maximum Ratings
- 7.2 ESD Ratings
- 7.3 Recommended Operating Conditions
- 7.4 Thermal Information
- 7.5 Electrical Characteristics: All Devices
- 7.6 Electrical Characteristics: TPS7H5001-SP
- 7.7 Electrical Characteristics: TPS7H5002-SP
- 7.8 Electrical Characteristics: TPS7H5003-SP
- 7.9 Electrical Characteristics: TPS7H5004-SP
- 7.10 Typical Characteristics
-
8 Detailed Description
- 8.1 Overview
- 8.2 Functional Block Diagram
- 8.3
Feature Description
- 8.3.1 VIN and VLDO
- 8.3.2 Start-Up
- 8.3.3 Enable and Undervoltage Lockout (UVLO)
- 8.3.4 Voltage Reference
- 8.3.5 Error Amplifier
- 8.3.6 Output Voltage Programming
- 8.3.7 Soft Start (SS)
- 8.3.8 Switching Frequency and External Synchronization
- 8.3.9 Primary Switching Outputs (OUTA/OUTB)
- 8.3.10 Synchronous Rectifier Outputs (SRA and SRB)
- 8.3.11 Dead Time and Leading Edge Blank Time Programmability (PS, SP, and LEB)
- 8.3.12 Pulse Skipping
- 8.3.13 Duty Cycle Programmability
- 8.3.14 Current Sense and PWM Generation (CS_ILIM)
- 8.3.15 Hiccup Mode Operation (HICC)
- 8.3.16 External Fault Protection (FAULT)
- 8.3.17 Slope Compensation (RSC)
- 8.3.18 Frequency Compensation
- 8.3.19 Thermal Shutdown
- 8.4 Device Functional Modes
-
9 Application and Implementation
- 9.1 Application Information
- 9.2
Typical Application
- 9.2.1 Design Requirements
- 9.2.2
Detailed Design Procedure
- 9.2.2.1 Switching Frequency
- 9.2.2.2 Output Voltage Programming Resistors
- 9.2.2.3 Dead Time
- 9.2.2.4 Leading Edge Blank Time
- 9.2.2.5 Soft-Start Capacitor
- 9.2.2.6 Transformer
- 9.2.2.7 Main Switching FETs
- 9.2.2.8 Synchronous Rectificier FETs
- 9.2.2.9 RCD Clamp
- 9.2.2.10 Output Inductor
- 9.2.2.11 Output Capacitance and Filter
- 9.2.2.12 Sense Resistor
- 9.2.2.13 Hiccup Capacitor
- 9.2.2.14 Frequency Compensation Components
- 9.2.2.15 Slope Compensation Resistor
- 9.2.3 Application Curves
- 9.3 Power Supply Recommendations
- 9.4 Layout
- 10Device and Documentation Support
- 11Revision History
- 12Mechanical, Packaging, and Orderable Information
8.3.3 Enable and Undervoltage Lockout (UVLO)
There are several methods for enabling the TPS7H500x-SP through the EN pin. The pin can be tied directly to VLDO, which would allow for the device to be enabled as soon as the voltage on VLDO surpasses the rising edge voltage threshold of the EN pin. The pin can also be driven with an externally generated signal or a compatible PGOOD signal for instances in which sequencing is desired. Lastly, two resistors can be used to program the controller to enable when VIN surpasses a user determined threshold, as shown in Figure 8-5. The two resistors are configured as a divider, with one between VIN and EN and the other between EN and AVSS.
Figure 8-5 Enable Pin Configuration Using
Two External ResistorsUsing Equation 1, the user can calculate the value for RUVLO_TOP for a chosen value of RUVLO_BOT based on the desired maximum start-up voltage for the device. With these selected resistors Equation 2 can be used to determine the minimum start-up voltage.
In the two-resistor configuration of Figure 8-5, the controller will also shut down due to undervoltage lockout when the input voltage falls below a particular threshold. This is due to the hysteresis of the EN pin. In order to determine the voltages at which shutdown is expected to occur, use Equation 3 and Equation 4.
It is important to note that the user should take care when selecting the values for RUVLO_TOP and RUVLO_BOT. It is recommended to optimize the selection of these resistors for start-up in order to ensure proper operation. The UVLO value must be approximately 75% or less of the input voltage in order to ensure that the device turns on as expected under all circumstances. Setting the UVLO any higher may cause issues with the turn-on of the device. Figure 8-6 shows the expected start-up and UVLO voltages on a 12-V rail where the maximum start-up voltage is 90% of the nominal input voltage. In this instance, turn-off will occur when the input voltage falls to between 75% and 65% of its nominal value.
Figure 8-6 Start-Up
and UVLO Values for Two-Resistor Configuration
With
VIN = 12 V