ZHCSMX7A August 2021 – December 2021 TPS92519-Q1
PRODUCTION DATA
- 1 特性
- 2 應(yīng)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 Buck Converter Switching Operation
- 7.3.2 Switching Frequency and Adaptive On-Time Control
- 7.3.3 Minimum On-Time, Off-Time, and Inductor Ripple
- 7.3.4 Enable
- 7.3.5 LED Current Regulation and Error Amplifier
- 7.3.6 Start-up Sequence
- 7.3.7 Analog Dimming and Forced Continuous Conduction Mode
- 7.3.8 External PWM Dimming and Input Undervoltage Lockout (UVLO)
- 7.3.9 Shunt FET Dimming or Matrix Beam Application
- 7.3.10 Bias Supply
- 7.3.11 Bootstrap Supply
- 7.3.12 Faults and Diagnostics
- 7.3.13 Output Short Circuit Fault
- 7.3.14 Output Open Circuit Fault
- 7.3.15 Parallel Operation
- 7.4 Device Functional Modes
-
8 Application and Implementation
- 8.1
Application Information
- 8.1.1 Duty Cycle Consideration
- 8.1.2 Switching Frequency Selection
- 8.1.3 LED Current Set Point
- 8.1.4 Inductor Selection
- 8.1.5 Output Capacitor Selection
- 8.1.6 Input Capacitor Selection
- 8.1.7 Bootstrap Capacitor Selection
- 8.1.8 Compensation Capacitor Selection
- 8.1.9 Input Undervoltage Protection
- 8.1.10 CSN Protection Diode
- 8.2
Typical Application
- 8.2.1 Design Requirements
- 8.2.2
Detailed Design Procedure
- 8.2.2.1 Calculating Duty Cycle
- 8.2.2.2 Calculating Minimum On-Time and Off-Time
- 8.2.2.3 Minimum Switching Frequency
- 8.2.2.4 LED Current Set Point
- 8.2.2.5 Inductor Selection
- 8.2.2.6 Output Capacitor Selection
- 8.2.2.7 Bootstrap Capacitor Selection
- 8.2.2.8 Compensation Capacitor Selection
- 8.2.2.9 PWM Dimming and Input Voltage Protection
- 8.2.3 Application Curves
- 8.1
Application Information
- 9 Power Supply Recommendations
- 10Layout
- 11Device and Documentation Support
- 12Mechanical, Packaging, and Orderable Information
封裝選項
機(jī)械數(shù)據(jù) (封裝 | 引腳)
- DAP|32
散熱焊盤機(jī)械數(shù)據(jù) (封裝 | 引腳)
- DAP|32
訂購信息
7.3.9 Shunt FET Dimming or Matrix Beam Application
Figure 7-5 Shunt FET Dimming Transient ResponseThe TPS92519-Q1 is compatible with shunt FET dimming and LED Matrix Manager devices. The fast dynamic response and adaptive on-time control topology ensure near ideal current source behavior with minimum inductor current overshoot or undershoot. In contrast to constant off-time control, the control loop is able to maintain LED current regulation under shorted output condition. The off-time of the converter naturally adapts to the inductor slope and valley command while keeping the average LED current constant. Figure 7-5 shows the shunt-FET dimming transient with all LEDs switched from on to off.
The device behavior is impacted by the falling slew-rate of CSN node, VCSN. A large slew-rate in conjunction with the parasitic capacitances from CSP and CSN to GND results in differential voltage forcing the converter to burst with minimum on-time and minimum off-time. To avoid switch node bursting TI recommends a maximum slew-rate (dv/dt) of 15 V/μs.