ZHCSMJ2 March 2021 TPS92390
PRODUCTION DATA
- 1 特性
- 2 應用
- 3 說明
- 4 Revision History
- 5 Pin Configuration and Functions
- 6 Specifications
-
7 Detailed Description
- 7.1 Overview
- 7.2 Functional Block Diagram
- 7.3
Feature Description
- 7.3.1 Control Interface
- 7.3.2 Function Setting
- 7.3.3 Device Supply (VDD)
- 7.3.4 Enable (EN)
- 7.3.5 Charge Pump
- 7.3.6 Boost Controller
- 7.3.7 LED Current Sinks
- 7.3.8 Brightness Control
- 7.3.9
Protection and Fault Detections
- 7.3.9.1 Supply Faults
- 7.3.9.2
Boost Faults
- 7.3.9.2.1 Boost Overvoltage Faults (BSTOVPL, BSTOVPH)
- 7.3.9.2.2 Boost Overcurrent Faults (BSTOCP)
- 7.3.9.2.3 LEDSET Resistor Missing Faults (LEDSET)
- 7.3.9.2.4 MODE Resistor Missing Faults (MODESEL)
- 7.3.9.2.5 FSET Resistor Missing Faults (FSET)
- 7.3.9.2.6 ISET Resistor Out of Range Faults (ISET)
- 7.3.9.2.7 Thermal Shutdown Faults (TSD)
- 7.3.9.3 LED Faults
- 7.3.9.4 Overview of the Fault and Protection Schemes
- 7.4 Device Functional Modes
- 7.5 Programming
- 7.6 Register Maps
-
8 Application and Implementation
- 8.1 Application Information
- 8.2
Typical Applications
- 8.2.1
Full Feature Application for Display Backlight
- 8.2.1.1 Design Requirements
- 8.2.1.2
Detailed Design Procedure
- 8.2.1.2.1 Inductor Selection
- 8.2.1.2.2 Output Capacitor Selection
- 8.2.1.2.3 Input Capacitor Selection
- 8.2.1.2.4 Charge Pump Output Capacitor
- 8.2.1.2.5 Charge Pump Flying Capacitor
- 8.2.1.2.6 Output Diode
- 8.2.1.2.7 Switching FET
- 8.2.1.2.8 Boost Sense Resistor
- 8.2.1.2.9 Power-Line FET
- 8.2.1.2.10 Input Current Sense Resistor
- 8.2.1.2.11 Feedback Resistor Divider
- 8.2.1.2.12 Critical Components for Design
- 8.2.1.3 Application Curves
- 8.2.2 Application With Basic/Minimal Operation
- 8.2.3
SEPIC Mode Application
- 8.2.3.1 Design Requirements
- 8.2.3.2
Detailed Design Procedure
- 8.2.3.2.1 Inductor Selection
- 8.2.3.2.2 Coupling Capacitor Selection
- 8.2.3.2.3 Output Capacitor Selection
- 8.2.3.2.4 Input Capacitor Selection
- 8.2.3.2.5 Charge Pump Output Capacitor
- 8.2.3.2.6 Charge Pump Flying Capacitor
- 8.2.3.2.7 Switching FET
- 8.2.3.2.8 Output Diode
- 8.2.3.2.9 Switching Sense Resistor
- 8.2.3.2.10 Power-Line FET
- 8.2.3.2.11 Input Current Sense Resistor
- 8.2.3.2.12 Feedback Resistor Divider
- 8.2.3.2.13 Critical Components for Design
- 8.2.3.3 Application Curves
- 8.2.1
Full Feature Application for Display Backlight
- 9 Power Supply Recommendations
- 10Layout
- 11Device and Documentation Support
- 12Mechanical, Packaging, and Orderable Information
8.2.3.2.1 Inductor Selection
Inductance for both inductors can be selected from Table 8-6, depending on operating frequency for the application. Current rating is recommended to be at least 25% higher than maximum inductor peak current. Peak-to-peak ripple current can be estimated to be approximately 40% of the maximum input current and and inductor peak current can be calculated with Equation 24, Equation 25, and Equation 26:
Table 8-6 Inductance Values for SEPIC Switching Frequencies
| SW FREQUENCY (kHz) | INDUCTANCE (μH) |
|---|---|
| 100 | 22 |
| 200 | 15 |
| 303 | 10 |
| 400 | 10 |
| 500 | 10 |
| 1818 | 4.7 |
| 2000 | 4.7 |
| 2222 | 4.7 |
Equation 24. 
where
- IL1(peak): Peak current for inductor 1
- IOUT: Maximum output current
- VOUT: Output voltage
- VD: Diode forward voltage drop
- VIN(min): Minimum input voltage
Equation 25. 
where
- IL2(peak): Peak current for inductor 2
- IOUT: Maximum output current
Equation 26. 
where
- ΔIL: Inductor ripple current
- IIN: Input current
- VOUT: Output voltage
- VIN(min): Minimum input voltage