Features

Suitable for car applications

AEC-Q100 to meet the following results:

-Equipment temperature level 1: --40 ° C To 125 ° C The temperature range of the environment

- Equipment HBM ESD level H2

- Device CDM ESD classification level C4B

Motor drive

-Drives two step motors, one step motor and two DC motors or four DC motors

-The current of each winding is as high as 1.5-a

[

[ 123] - Low -conducting resistance

- Programmable maximum winding current

- Three -level winding current control allows up to eight currents Or mixed attenuation mode

8-v to 32-v working power supply voltage range

internal charging pump

#8226 ; Built-in 3.3-v reference

serial digital control interface

to prevent pressure, overheating, and over current

# 8226; thermal enhancement surface installation component

Application

Auto

DRV8823-Q1

The device is a printer and other office Automated equipment applications provide integrated motor driver solutions.

The motor drive circuit includes four H bridge drivers. Each person's motor drive module uses N -channel power MOSFET as the H bridge to drive the motor winding. A simple serial interface only requires a few digital signals to control all functions of the motor drive. It also provides low -power sleep functions.

The motor driver provides PWM current control capabilities. A current programmable, based on the reference voltage and external current detection resistor provided by the outside. In addition, eight current levels (setting through serial interface) allows bipolar steps to step into the motor.

Provide internal shutdown functions of overcurrent protection, short -circuit protection, low -voltage locking and ultra -temperature.

DRV8823-Q1 uses 48-pin HTSSOP packaging (environmentally friendly: ROHS and NO SB/BR).

Equipment information

(1), please refer to the appointment appendix at the end of the data table.

Simplify the schematic diagram

Typical feature

Detailed description Overview DRV8823-Q1 is a double step The motor driver solution is suitable for automotive applications that need to control two different motors independently. The device integrates four NMOS H bridges, a micro -step attractor, and various fault protection functions. The power supply voltage of DRV8823-Q1 is between 8V and 32V and can provide an output current up to 1.5A full range. The actual full -standard current will depend on the size of the ambient temperature, power supply voltage and PCB grounding size.

Including a serial data interface to control all the functions of the motor drive. The current adjustment through all four HBRIDGE is achieved by each H bridge with three registers. These three register bits are used to zoom in the current of each bridge according to the percentage of the full marked current set by the VREF input pin and sensing resistance settings. The current adjustment can be configured with two different attenuation modes: slow attenuation and hybrid attenuation.

Control the grid driver of each field effect of all four H bridges to prevent any cross -conduction (penetrating current) in the transition process.

Function box diagram

Feature description

PWM motor drive

DRV8823-Q1 device contains four band current control The H bridge motor driver of the PWM circuit. FIG. 11 shows the frame diagram of the driver A and B of the motor control circuit A and B (usually used to drive the bipolar step motor). Drives C and D are the same as A and B (although the RDS (ON) of FET is different).

Please note that there are multiple VM motor power sources. All VM pins must be connected to the motor voltage.

Protective circuit

DRV8823-Q1 equipment has sufficient protection to prevent pressure, over current and overheating events.

Overcurrent protection (OCP)

All drivers in the DRV8823-Q1 device are protected by over-current protection (OCP) circuits.

The OCP circuit includes an analog current restriction circuit. When the current of the circuit exceeds the preset level, the circuit works by removing the gate driver of each output FET. This circuit limits the current to a safe level to prevent damage to FET.

Digital circuit monitoring simulation of current limits circuit. If the time of any simulation current restrictions exceeds the preset time, all the drivers in the device will be disabled.

After removing and re -applied the power supply on the VM pin, the device will be reopened.

Hot shutdown (TSD) [TSD) [TSD)

If the mold temperature exceeds the safety limit, all the drivers in the device will be closed.

Before the temperature of the mold drops to the safe level, the device remains disabled. After the temperature drops, the device can be reorganized after removing and re -application of VM pins.

IOU locking (UVLO)

If the voltage on the VM pin is lower than the voltage of the underwriting lock at any time, all circuits in the device will be disabled. When the VM rises to the UVLO threshold, the operation recovers. If UVLO occurs, the index logic will be reset to the initial state.

Stepping current protection

Control the grille driver of each field effect in the H bridge to prevent any cross -conduction (penetrating current) during the transition.

Equipment function mode

Bridge control

When setting to 1, the XenBL bit in the serial interface register enables the current flow in each H bridge.

The XPHASE bit in the serial interface register is controlled through the current direction of each H bridge. Table 1 shows logic.

current adjustment

The motor driver uses a fixed frequency PWM current adjustment (also known as current cutting wave). When a winding is activated, the current rises until it reaches a threshold, and then the current is cut off until the next PWM cycle.

PWM frequency is fixed at 50 kHz, but it can also be set to 100 kHz by the factory option.

The PWM cut wave current is set by the comparator, and the voltage of the current influenza resistor connected to the XISEN pins will be compared by comparing the voltage of the resistor to the XISEN pin. The reference voltage is input from the VREF pin.

Full range (100%) Calculation of cutting wave current as follows:

Example:

The resistor and the VREFX pin are 2.5 V, the full marker (100%) cutting current is: 2.5 V/(5 × 0.5 ) 1 A.

Each H bridge uses three serial interface storage positions (xi2, xi1, and xi0), and the percentage of the full volume current set by VREF input pins and sensing resistance is zoomed in each bridge in each bridge Current. The function of the bit is shown in Table 2.

The decay mode

During the PWM current cut, the H bridge can drive the motor winding until the PWM current cut threshold is reached. This shows case 1 in FIG. 12. The current direction displayed in Figure 12 indicates a positive current.

Once you reach the chopThe wave current threshold, the H bridge can work in two different states, fast attenuation or slow attenuation.

In the fast attenuation mode, once the PWM cutting current level is reached, the H bridge will reverse to allow the winding current reverse flow. When the winding current is close to zero, the bridge is banned to prevent any reverse current flow. The fast attenuation mode is shown in the situation 2 in Figure 12.

Under low -current mode, the bridge winding is slowly attenuated under the low -current attenuation mode. This is shown in Figure 12 as Case 3.

DRV8823-Q1 device supports slow attenuation and mixed attenuation mode. The hybrid attenuation mode starts with rapid attenuation, but switches to the slow attenuation mode at a fixed period of time (75%of the PWM cycle) to switch to the slow attenuation mode within the remaining time of the fixed PWM cycle.

Slow decay or mixed decaying mode is selected by the status of the XDECAY bit in the serial interface register. If the XDECAY bit is 0, choose to be attenuated slowly. If the XDECAY bit is 1, choose a mixed recession.

Sweeding time

After the current is enabled in the H bridge, the voltage on the Xisen pins will be ignored before the current detection circuit is enabled. The hidden time is fixed to 3.75μs. Note that the hidden time also sets up the minimum connection time of PWM. 7.5 Programming

Serial data transmission

It consists of 16 -bit serial data transmission of the first LSSData.

When writing serially on the DRV8823-Q1 device, the edge of the additional clock after the final data bit continues to move the data bit to the data register; therefore, the last 16 bits were locked and used.

One of the two registers is selected by the bit of the four high -bit address fields that set serial data (ADDR in the table below). One 16 -bit register is used to control No. 1 motor (bridge A and B), and the other 16 -bit register is used to control motor 2 (bridge C and D).

Only when the SCS input pin is at high electricity, the data can be transmitted to the serial interface.

The data was initially recorded in a temporary retail. The data is locked in the motor drive rising along the SSTB pin. If the SSTB tube foot is always high, the data will be locked after all 16 -bit transmission.

Application and Implement For part of, TI does not guarantee its accuracy or integrity. TI's customers are responsible for determining the applicability of the component. Customers should verify and test their design implementation to confirm the system function.

Application information

DRV8823-Q1 can be used to drive two dual-pole step into the motor.

Typical application

Design requirements

Table 5 lists the design requirements of the design example.

Detailed design program

motor voltage

Appropriate motor voltage depends on the rated value of the selected motor and the required torque required torque. Essence The higher voltage shortens the current rising time in the step motor coil and allows a larger average torque. Using higher voltage can also make the motor run at a faster voltage and faster speed.

Drive current

The current path runs to the motor starts from the power VM, and then passes through the high -side NMOS power FET, through the sensor winding load of the motor, and then sinks the NMOS power FET through the low -side sinking NMOS power FET. , Finally through external sensing resistors. The power loss of the two NMOS power FET inside DRV8823-Q1 is shown in the following formula.

DRV8823-Q1 at a standard FR-4 PCB packaging at a standard FR-4 PCB to measure the continuous current of 1.5-A. The maximum continuous current will change according to the PCB design and environmental temperature.

Application curve

Power suggestion

It is an important factor in the design of the motor drive system. Generally speaking, more volume capacitors are beneficial, but the disadvantage is increased cost and physical dimensions. The required local power capacity depends on multiple factors, including:

the highest current required for the motor system

]

Parasitic inductance between the power supply and the motor system

acceptable voltage ripple

Brush DC, brushless DC, step motor)

Electrical braking method

The inductance between the power supply and the motor drive system will limit the change rate of power current. If the local large -capacity capacitance is too small, the system will respond to excessive current requirements, or uninstall from the motor as the voltage changes. When using sufficient large -capacity capacitors, the motor voltage remains stable and can quickly provide large current.

The data table usually provides a recommended value, but it is necessary to perform system -level tests to determine large -capacity capacitors with appropriate size.

The rated voltage of a large capacitor should be highIn the working voltage so that the motor is provided to the power supply to the power supply energy.

Layout

Layout Guide

The placement of large -capacity capacitors should be reduced as much as possible to drive the distance from the large current path of the motor -driven device. The width of the metal trace line should be as wide as possible, and multiple excess perforated should be used when connecting the PCB layer. These methods minimize the inductance and allow large capacitor to transport high current.

Small capacitors should be ceramic and placed in a place where the device pin is very close.

The output of high -current equipment shall use wide metal traces.

The equipment hot pad should be welded on the floor floor floor of the PCB. Multiple pores should be used to connect to large bottom ground planes. Use large metal planes and multiple holes to help the I2 × RDS (ON) heat generated in the dissipation device.

Layout example

Heat Precautions

DRV8823-Q1 device has the heat shutdown (TSD) as described above. If the mold temperature exceeds about 150 ° C, the device will be disabled until the temperature drops to the safe level.

Any trend of the device's entry into the heat stack indicates that the power consumption is too large, insufficient heat dissipation, or the environmental temperature is too high.

Power consumption

The power consumption of the DRV8823-Q1 device is mainly controlled by the output FET resistance or RDS (on). The average power consumption of the step motor can be roughly estimated by the equation 3.

In the formula: PTOT is the total power consumption, RDS (on) is the resistance of each FET, and IOUT (RMS) is an RMS output current for each winding. IOUT (RMS) is about 0.7 times that of the full marking output current settings. Coefficient 4 comes from the two motor winding, and at any time, the two FETs are conducted by each winding winding winding current (one high -voltage side and one low -voltage side). The DRV8823-Q1 device has two step motor drives, so the power consumption of each driver must be added to determine the total power consumption of the equipment.

The maximum power that can be consumed in the DRV8823-Q1 device depends on the ambient temperature and heat dissipation. The thermal dispersing rated value table in the data table can be used to estimate the temperature rise of the typical PCB structure.

Note that RDS (on) increases as the temperature increases, so when the device is heated, the power consumption will increase. When determining the size of the heat sink, this must be considered.

Sinking

PowerPad integrated circuit packaging uses a bare pad to remove the heat in the device. In order to correctly operate, the pad must be connected to the copper heat on the PCB to dissipate heat. On the multi -layer PCB with the floor, this can be achieved by adding multiple holes to connect the hot pad to the horizonEssenceOn PCB without internal planes, you can add copper area to any side of the PCB to dissipate heat.If the copper zone is on the other side of the PCB, the thermal hole is used to convey the heat between the top and the bottom layer.

Generally speaking, the more copper area provided, the greater the consumption power.Figure 21 shows the relationship between a single -sided PCB with 2 ounces of copper heat sink and a 4 -layer PCB with 1 ounce copper and solid floor.The thickness of the two PCBs is 76 mm x 114 mm and 1.6 mm, respectively.The effectiveness of the heat dissipation sheet increased rapidly to about 20 square centimeters, and then decreased in a larger area.

Six pins on the center of the package are also connected to the device ground.The copper area can be used to connect to the PCB encapsulated by the PowerPad integrated circuit, and it can also be used to connect all ground pins on each side of the device, which is particularly useful for a single -layer PCB design.