ZHCSJY0B June 2012 – June 2019 LMR12015 , LMR12020
PRODUCTION DATA.
- 1 特性
- 2 應(yīng)用
- 3 說明
- 4 修訂歷史記錄
- 5 Pin Configuration and Functions
- 6 Specifications
- 7 Detailed Description
-
8 Application and Implementation
- 8.1 Application Information
- 8.2
Typical Application
- 8.2.1
Detailed Design Procedure
- 8.2.1.1 Custom Design With WEBENCH® Tools
- 8.2.1.2 Inductor Selection
- 8.2.1.3 Input Capacitor
- 8.2.1.4 Output Capacitor
- 8.2.1.5 Catch Diode
- 8.2.1.6 Boost Diode (Optional)
- 8.2.1.7 Boost Capacitor
- 8.2.1.8 Output Voltage
- 8.2.1.9 Feedforward Capacitor (Optional)
- 8.2.1.10
Calculating Efficiency and Junction Temperature
- 8.2.1.10.1 Schottky Diode Conduction Losses
- 8.2.1.10.2 Inductor Conduction Losses
- 8.2.1.10.3 MOSFET Conduction Losses
- 8.2.1.10.4 MOSFET Switching Losses
- 8.2.1.10.5 IC Quiescent Losses
- 8.2.1.10.6 MOSFET Driver Losses
- 8.2.1.10.7 Total Power Losses
- 8.2.1.10.8 Efficiency Calculation Example
- 8.2.1.10.9 Calculating the LMR2015/20 Junction Temperature
- 8.2.2 Application Curves
- 8.2.3 LMR12015/20 Circuit Examples
- 8.2.1
Detailed Design Procedure
- 9 Layout
- 10器件和文檔支持
- 11機(jī)械、封裝和可訂購信息
封裝選項
機(jī)械數(shù)據(jù) (封裝 | 引腳)
- DSC|10
散熱焊盤機(jī)械數(shù)據(jù) (封裝 | 引腳)
- DSC|10
訂購信息
8.2.1.10.8 Efficiency Calculation Example
Operating conditions are:
Equation 44. VIN = 12 V
Equation 45. fSW = 2 MHz
Equation 46. VOUT = 3.3 V
Equation 47. VD1 = 0.5 V
Equation 48. IOUT = 2 A
Equation 49. RDCR = 20 mΩ
Internal Power Losses are:
Equation 50. PCOND = IOUT2 × RDSON x D= 22 × 0.15 Ω × 0.314 = 188 mW
Equation 51. PSW = (VIN x IOUT × ƒSW × tFALL) = (12 V × 2 A x 2 MHz × 10n s) = 480 mW
Equation 52. PQ = IQ × VIN = 2.4 mA × 12 V = 29 mW
Equation 53. PBOOST = IBOOST × VBOOST = 8.2 mA x 4.5V = 37 mW
Equation 54. PINTERNAL = PCOND + PSW + PQ + PBOOST = 733 mW
Total power losses are:
Equation 55. PDIODE= VD1 × IOUT (1 – D) = 0.5 V × 2 × (1 – 0.314) = 686 mW
Equation 56. PIND= IOUT2 × RDCR = 22 × 20 mΩ = 80 mW
Equation 57. PLOSS = PINTERNAL + PDIODE + P IND = 1.499 W
The efficiency can now be estimated as:
Equation 58. 
With this information we can estimate the junction temperature of the LMR12015/20.