ZHCSPQ7A december 2022 – april 2023 MCT8315A
PRODUCTION DATA
- 1
- 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 Output Stage
- 7.3.2 Device Interface
- 7.3.3 Step-Down Mixed-Mode Buck Regulator
- 7.3.4 AVDD Linear Voltage Regulator
- 7.3.5 Charge Pump
- 7.3.6 Slew Rate Control
- 7.3.7 Cross Conduction (Dead Time)
- 7.3.8 Speed Control
- 7.3.9 Starting the Motor Under Different Initial Conditions
- 7.3.10 Motor Start Sequence (MSS)
- 7.3.11 Closed Loop Operation
- 7.3.12 Speed Loop
- 7.3.13 Input Power Regulation
- 7.3.14 Anti-Voltage Surge (AVS)
- 7.3.15 Output PWM Switching Frequency
- 7.3.16 Fast Start-up (< 50 ms)
- 7.3.17 Fast Deceleration
- 7.3.18 Active Demagnetization
- 7.3.19 Motor Stop Options
- 7.3.20 FG Configuration
- 7.3.21
Protections
- 7.3.21.1 VM Supply Undervoltage Lockout
- 7.3.21.2 AVDD Undervoltage Lockout (AVDD_UV)
- 7.3.21.3 BUCK Undervoltage Lockout (BUCK_UV)
- 7.3.21.4 VCP Charge Pump Undervoltage Lockout (CPUV)
- 7.3.21.5 Overvoltage Protection (OVP)
- 7.3.21.6 Overcurrent Protection (OCP)
- 7.3.21.7 Buck Overcurrent Protection
- 7.3.21.8
Cycle-by-Cycle (CBC) Current Limit (CBC_ILIMIT)
- 7.3.21.8.1 CBC_ILIMIT Automatic Recovery next PWM Cycle (CBC_ILIMIT_MODE = 000xb)
- 7.3.21.8.2 CBC_ILIMIT Automatic Recovery Threshold Based (CBC_ILIMIT_MODE = 001xb)
- 7.3.21.8.3 CBC_ILIMIT Automatic Recovery after 'n' PWM Cycles (CBC_ILIMIT_MODE = 010xb)
- 7.3.21.8.4 CBC_ILIMIT Report Only (CBC_ILIMIT_MODE = 0110b)
- 7.3.21.8.5 CBC_ILIMIT Disabled (CBC_ILIMIT_MODE = 0111b or 1xxxb)
- 7.3.21.9 Lock Detection Current Limit (LOCK_ILIMIT)
- 7.3.21.10 Thermal Warning (OTW)
- 7.3.21.11 Thermal Shutdown (TSD)
- 7.3.21.12 Motor Lock (MTR_LCK)
- 7.3.21.13 Motor Lock Detection
- 7.3.21.14 SW VM Undervoltage Protection
- 7.3.21.15 SW VM Overvoltage Protection
- 7.3.21.16 IPD Faults
- 7.4 Device Functional Modes
- 7.5 External Interface
- 7.6 EEPROM access and I2C interface
- 7.7 EEPROM (Non-Volatile) Register Map
- 7.8 RAM (Volatile) Register Map
- 8 Application and Implementation
- 9 Power Supply Recommendations
- 10Layout
- 11Device and Documentation Support
- 12Mechanical, Packaging, and Orderable Information
封裝選項(xiàng)
機(jī)械數(shù)據(jù) (封裝 | 引腳)
- RGF|40
散熱焊盤機(jī)械數(shù)據(jù) (封裝 | 引腳)
- RGF|40
訂購信息
7.3.16.1 BEMF Threshold
Figure 7-37 shows the three-phase voltages during 120o trapezoidal operation. It is seen that one of the phases will always be floating within a 60o commutation interval and MCT8315A integrates this floating phase voltage (which denotes the motor back-EMF) in the back-EMF integration method to detect the next commutation instant. The floating phase voltage can either be increasing or decreasing and the algorithm starts the integration after the zero cross detection in order to eliminate integration errors due to variable degauss time. The floating phase voltage is periodically sampled (after zero cross) and added (discrete form of integration). BEMF threshold (BEMF_THRESHOLD1 and BEMF_THRESHOLD2) value is set such that the integral value of the floating phase voltage crosses the BEMF_THRESHOLD1 or BEMF_THRESHOLD2 value at (or very near) to the commutation instant. BEMF_THRESHOLD1 is the threshold for rising floating phase voltage and BEMF_THRESHOLD2 is the threshold for falling floating phase voltage. If BEMF_THRESHOLD2 is set to 0, then BEMF_THRESHOLD1 is used as the threshold for both rising and falling floating phase voltage.
Figure 7-37 Back-EMF integration using
floating phase voltageIn Figure 7-37 , Vpeak is the peak-peak value of the back-EMF , Vpeak/2 denotes the zero cross of the back-EMF and Tc is the commutation interval or time period of the 60o window. The highlighted triangle in each 60o window is the integral value of back-EMF used by the algorithm to determine the commutation instant. This integral value, which can be approximated as the area of the highlighted triangle, is given by Equation 7.
See for an example application on setting the BEMF threshold.