Features

* for a8902Clba Sales and replacement sales

* Start the conversion circuit

*No sensor switching circuit

*Select the external sector data speed table signal

*External speed control option

*oscillator operates as much as 20 mHz [ 123]

*Programmable overcurrent limit

*Cross -guidance gain option: 500 mAh/volt or 250 mAh/volt

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*direction control

*serial port interface

*TTL compatible input

*Real -time output system diagnosis data

Dynamic brakes in port or external terminals

A8904SLB and A8904SLP are three -phase brush -free DC motor controller/driver design for the application of accurate control of high -speed motors. The three semi -bridge output is a low -conducting resistance N -channel DMOS device, which can drive up to 1.2 A and A8904 to provide complete, reliable and independent anti -electrocompany sensing, motor startup and operation algorithm. The programmable digital lock ring speed control circuit and linear current control circuit provide accurate motor speed adjustment together.

The serial port allows users to operate, such as speed control parameters, start -up current limit, sleep mode, direction and diagnostic mode.

A8904 uses Allegro's BCD (dual -pole CMOS DMO) production process, a advanced hybrid signal technology, combined with double pole, analog and digital CMOS and DMOS power devices. The A8904SLB uses a 24 -drawing wide -body SOIC bat wing component. A8904SLP uses thin ( lt; 1.2 MM), 28 lead SSOP packaging, with exposed heat pads. Each type of packaging has a lead -free version (100%matte tin lead framework).

Always order according to the complete part number:

function box diagram

[ 123] Function description

Operation summary. Each electric rotation contains six states to control three semi -bridge output. Optimized switching from the state to the state through the adaptive conversion circuit. In any state, one output is high, one is low, and the other is high. The anti -electromotive force of the high impedance output terminal is sensing and compared with the voltage of the center tap. When the two signals are equal, the FCOM signal is switched. The control delay was then introduced before the serial transition was converted to the next state.

Use linear current modeControl, while maintaining extremely low -electric noise emissions, accurately control the motor speed. The speed control is achieved by the frequency locking ring. The frequency lock the ring processing the stator phase -phase anti -electromotive motivation signal, and the speed signal is finally generated. Then compare the speed meter signal with the required programming speed to generate errors. The error signal is then used for linear control through the current of the low -side DMOS power supply to obtain the correct speed.

Can introduce alternative control solutions to provide users with maximum flexibility and optimization for each application. The external speed meter signal applied to the sector data input and internal speed reference can be used for high -precision speed control. As another option, users can introduce external speed control by direct drive filter terminal.

The startup program is inherent in the solution to ensure reliable startup. During the startup process, Yangkert allows quickly transition to the nominal working conditions of the filter terminal. This function is also available when using external speed control.

Dynamic brakes can be introduced through external braking terminals or braking positions in the serial port.

The serial port allows users to program various characteristics and operating modes, such as motor speed, internal or external speed control, internal or external speed reference, current restrictions, sleep mode, direction, charging current (for elimination of hidden hidden hidden Pulse), motor pole, cross -guided gain and various diagnostic outputs.

The protection of the entire device includes a programmable over -current restriction, heat shutdown and logical power supply pressure shutdown.

Power output. The power output of the A8904 is the N -channel DMOS transistor. The total source plus the receiver RDS (on) is usually 1Ω. The internal charge pump provides a voltage rail above the load power supply to drive the high -side DMOS gate. The ground migrants and anti -gratic diode provide protection when switching the inductance load. These diode will also corrected the electrostatic motor of the motor under power off. If necessary, the transient voltage power supply can be provided by connecting an external Schottky power diode or connected FET between the power supply and the load power supply (VBB). This field -effect transistor or diode effectively isolates the low impedance path through the power supply. The filter capacitor also needs to maintain " the rectifier signal and connect between the load power and ground.

The starting and operation algorithm of the electromotive force sensing motor. The A8904 provides a complete self -sufficient anti -electromotive force sensing