ZHCSEP5D January 2016 – November 2018 DRV8884
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
- 7.1 Overview
- 7.2 Functional Block Diagram
- 7.3
Feature Description
- 7.3.1 Stepper Motor Driver Current Ratings
- 7.3.2 PWM Motor Drivers
- 7.3.3 Microstepping Indexer
- 7.3.4 Current Regulation
- 7.3.5 Controlling RREF With an MCU DAC
- 7.3.6 Decay Modes
- 7.3.7 Blanking Time
- 7.3.8 Charge Pump
- 7.3.9 LDO Voltage Regulator
- 7.3.10 Logic and Multi-Level Pin Diagrams
- 7.3.11 Protection Circuits
- 7.4 Device Functional Modes
- 8 Application and Implementation
- 9 Power Supply Recommendations
- 10Layout
- 11器件和文檔支持
- 12機(jī)械、封裝和可訂購信息
封裝選項(xiàng)
機(jī)械數(shù)據(jù) (封裝 | 引腳)
散熱焊盤機(jī)械數(shù)據(jù) (封裝 | 引腳)
訂購信息
9.1 Bulk Capacitance
Having appropriate local bulk capacitance is an important factor in motor drive system design. It is generally beneficial to have more bulk capacitance, while the disadvantages are increased cost and physical size.
The amount of local capacitance needed depends on a variety of factors, including:
- The highest current required by the motor system
- The power supply’s capacitance and ability to source current
- The amount of parasitic inductance between the power supply and motor system
- The acceptable voltage ripple
- The type of motor used (brushed DC, brushless DC, stepper)
- The motor braking method
The inductance between the power supply and motor drive system will limit the rate current can change from the power supply. If the local bulk capacitance is too small, the system will respond to excessive current demands or dumps from the motor with a change in voltage. When adequate bulk capacitance is used, the motor voltage remains stable and high current can be quickly supplied.
The data sheet generally provides a recommended value, but system-level testing is required to determine the appropriate sized bulk capacitor.
The voltage rating for bulk capacitors should be higher than the operating voltage, to provide margin for cases when the motor transfers energy to the supply.
Figure 31. Example Setup of Motor Drive System With External Power Supply