ZHCSTC5B October 2023 – June 2024 LM51772
PRODUCTION DATA
- 1
- 1 特性
- 2 应用
- 3 说明
- 4 Pin Configuration and Functions
- 5 Specifications
- 6 Parameter Measurement Information
-
7 Detailed Description
- 7.1 Overview
- 7.2 Functional Block Diagram
- 7.3
Feature Description
- 7.3.1 Buck-Boost Control Scheme
- 7.3.2 Power Save Mode
- 7.3.3 Programmable Conduction Mode PCM
- 7.3.4 Reference System
- 7.3.5 Supply Voltage Selection – VSMART Switch and Selection Logic
- 7.3.6 Enable and Undervoltage Lockout
- 7.3.7 Internal VCC Regulators
- 7.3.8 Error Amplifier and Control
- 7.3.9 Output Voltage Discharge
- 7.3.10 Peak Current Sensor
- 7.3.11 Short Circuit - Hiccup Protection
- 7.3.12 Current Monitor/Limiter
- 7.3.13 Oscillator Frequency Selection
- 7.3.14 Frequency Synchronization
- 7.3.15 Output Voltage Tracking
- 7.3.16 Slope Compensation
- 7.3.17 Configurable Soft Start
- 7.3.18 Drive Pin
- 7.3.19 Dual Random Spread Spectrum – DRSS
- 7.3.20 Gate Driver
- 7.3.21 Cable Drop Compensation (CDC)
- 7.3.22 CFG-pin and R2D Interface
- 7.3.23 Advanced Monitoring Features
- 7.3.24
Protection Features
- 7.3.24.1 Thermal Shutdown (TSD)
- 7.3.24.2 Over Current Protection
- 7.3.24.3 Output Over Voltage Protection 1 (OVP1)
- 7.3.24.4 Output Over Voltage Protection 2 (OVP2)
- 7.3.24.5 Input Voltage Protection (IVP)
- 7.3.24.6 Input Voltage Regulation (IVR)
- 7.3.24.7 Power Good
- 7.3.24.8 Boot-Strap Under Voltage Protection
- 7.3.24.9 Boot-strap Over Voltage Clamp
- 7.3.24.10 CRC - CHECK
- 7.4 Device Functional Modes
- 7.5 Programming
- 8 LM51772 Registers
-
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 Custom Design with WEBENCH Tools
- 9.2.2.2 Frequency
- 9.2.2.3 Feedback Divider
- 9.2.2.4 Inductor and Current Sense Resistor Selection
- 9.2.2.5 Output Capacitor
- 9.2.2.6 Input Capacitor
- 9.2.2.7 Slope Compensation
- 9.2.2.8 UVLO Divider
- 9.2.2.9 Soft-Start Capacitor
- 9.2.2.10 MOSFETs QH1 and QL1
- 9.2.2.11 MOSFETs QH2 and QL2
- 9.2.2.12 Loop Compensation
- 9.2.2.13 External Component Selection
- 9.2.3 Application Curves
- 9.3 Power Supply Recommendations
- 9.4 Layout
- 9.5 USB-PD Source with Power Path
- 9.6 Parallel (Multiphase) Operation
- 9.7 Constant Current LED Driver
- 9.8 Wireless Charging Supply
- 9.9 Bi-Directional Power Backup
- 10Device and Documentation Support
- 11Revision History
- 12Mechanical, Packaging, and Orderable Information
5.7 Typical Characteristics
The following conditions apply (unless otherwise noted): TJ = 25°C; V(VCC2) = 5V
Figure 5-1 Switching Frequency Versus RT Resistance
Figure 5-3 FB Pin Reference Voltage
versus Temperature
Figure 5-5 Shutdown Current into VIN
versus Pin Voltage VEN/UVLO = 0V ,V(VIN) = 12V, V(BIAS) = 0V
Figure 5-7 Shutdown Current into BIAS
versus Temperature VEN/UVLO = 0V ,V(VIN) = 3.5V,V(BIAS) = 12V
Figure 5-9 Quiescent Current into
BIAS versus BIAS V(BIAS) = 12V , V(VIN) = 3.5V
Figure 5-11 VCC2 LDO Output voltage versus VCC2 Load CurrentV(VIN) = 12V, V(BIAS) = 0V
Figure 5-13 VCC2 LDO Output voltage versus VIN Voltage V(BIAS) = 0V
Figure 5-15 Soft-Start current versus
Temperature 
Figure 5-17 Hysteresis Current on
EN/UVLO versus Temperature 
Figure 5-19 Buck Minimum On-time versus Switching Frequency
Figure 5-21 Boost Minimum On-time
versus Switching Frequency
Figure 5-23 Gate Driver Transition (Dead) Time versus Switching Frequency SEL_MIN_DEADTIME_GDRV = 0b01,SEL_SCALE_DT = 0b1, EN_CONST_TDEAD = 0b0
Figure 5-25 Peak Current Limit
Threshold Voltage Versus Temperature
Figure 5-27 CSB Input Current versus Temperature 
Figure 5-29 Average Current Limit Threshold Voltage Versus Temperature ILIM_THRESHOLD = 0x3C
Figure 5-2 Switching Frequency versus Temperature R(RT) = 75KΩ
Figure 5-4 FB Pin Reference Voltage versus VO Register DAC-Code
Figure 5-6 Shutdown Current into VIN versus Temperature VEN/UVLO = 0V ,V(VIN) = 12V,V(BIAS) = 0V
Figure 5-8 Quiescent Current into
BIAS versus BIAS pin voltage V(VIN) = 3.5V
Figure 5-10 Standby Current into BIAS versus Temperature V(VIN) = 3.5V V(VIN) = 12V
Figure 5-12 VCC2 LDO Output voltage versus VCC2 Load CurrentV(VIN) = 3.5V, V(BIAS) = 12V
Figure 5-14 VCC2 LDO Output voltage versus BIAS Voltage V(VIN) = 2.5V
Figure 5-16 EN/UVLO Threshold versus Temperature 
Figure 5-18 Buck Minimum Off-time
versus Switching Frequency 
Figure 5-20 Boost Minimum Off-time versus Switching Frequency
Figure 5-22 Buck Minimum Duty -cycle
for PSM Operation versus Switching Frequency (SYNC_OUT = Enabled)
Figure 5-24 Gate Driver Transition (Dead) Time versus Switching Frequency f(sw) = 100kHz ,SEL_MIN_DEADTIME_GDRV = 0b01, EN_CONST_TDEAD = 0b0, Turn Low-Side off, Turn High-Side on
Figure 5-26 CSA Input Current versus Temperature
Figure 5-28 Average Current Limit
Threshold Voltage Versus Temperature ILIM_THRESHOLD = 0x64
Figure 5-30 Average Current Limit Threshold Voltage Versus Temperature ILIM_THRESHOLD = 0x14