Features

H bridge motor driver

low RDS (on) mosFet (0.4- typical value)

Low-power Sleep Mode

Support 100%PWM

8-V to 36-V working power supply voltage range

thermal enhancement surface installation component

Protection function:

-VBB IOlLL Lock (UVLO)

- Charging pump IOV (CPUV) (CPUV) (CPUV)

- Over -current protection (OCP)

- Short -circuit protection of power supply

- Short -circuit protection of the ground

- Overheating warning (OTW)

[ 123] -The ultra -temperature stop (OTS)

-The fault status indicator pin (nfault)

Application

printer

# 8226; Industrial Automation

Robot

Description

DRV880X

provides a multi -functional motor drive solution with a variety of functions. The device contains a complete H bridge that can be used to drive a winding motor, a stepping motor winding, or other devices such as a snail tube. A simple phase interface can easily connect to the controller circuit.

The output level uses N -channel power MOSFET as the H bridge. The peak output current of DRV880XIS can reach ± 2.8A, and the operating voltage is as high as 36V. The internal charge pump generates the required grid drive voltage.

A low -power dormant mode is provided, which shut down the internal circuit to achieve very low static current consumption. This sleep mode can be set using a special NSLEEP pin.

The internal protection function can be used for underold voltage, charge pump failure, overcurrent, short circuit to the power supply, short circuit and overheating on the ground. The failure state is instructions through the NFAULT pin.

DRV880X is encapsulated in 16 -pin wqfn packaging with PowerPad #8482;

Equipment information

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

Jane Figure

Typical features

123] Parameter measurement information

Detailed instruction Integrated motor solution of DC motor. These devices integrate the DMOS H bridge, protection circuit and simple digital interface. This device can be powered by 8 to 36 volts and can provide an output current up to 2.8 amp.

The phase enable interface is convenient to connect to the controller circuit. The phase input controls the direction of the H bridge, and enables the input to be enabled by the specified H bridge.

The two mode pins allow the current attenuation method used by the specified device. Mode 1 specifies fast attenuation or slow attenuation, and Mode 2 specifies high or low -side slow attenuation.

DRV8801 provides options for monitoring motor winding current through a proportional voltage output.

Figure Figure

Feature description

Logic input

TI suggestion Use a high -value resistor when the logic input is pulled to the VDD. The resistor limits the input current to prevent overvoltage events. Logic input is NSLEEP, Mode, Phase, and Enable. Any logical input voltage higher than 7V will damage the input structure.

Vreg (only DRV8800)

This output indicates the measurement value of the voltage of the internal regulator. This pin should be disconnected. This pin can be measured to about 7.5 V voltage.

VPROPI (only DRV8801)

This output provides an analog voltage that is proportional to the winding current. The voltage on this terminal is five times that of the motor winding current (VPROPI 5 × i). VPROPI is only meaningful when a resistor is connected to the detection pipe foot. If Sense is grounded, the VPROPI measurement value is 0 V. In the process of slow attenuation, VPROPI output 0 V. VPROPI can output a maximum of 2.5 V, because under the induction voltage of 500 MV, the H bridge is disabled.

The oil supply pump

The charge pump is used to generate a power supply higher than VBB to drive the DMOS door at the end of the source. A 0.1-μF ceramic single-chip capacitor should be connected between CP1 and CP2 to pump. A 0.1 μF ceramic single -sheet capacitor CSTRAGE is connected between VCP and VBB to run high -end DMOS devices as a reservoir. The VCP voltage level is monitored by internal monitoring, and the output of the device will be disabled under failure.

Shut down

As a measure of protection device, from a high knot temperature or low electricity on VCPThe failure caused by the pressure will fail the output of the device until the failure state is eliminated. When power is powered, the UVLO circuit disables the driver.

Low -power mode

Control the input NSLEEP to minimize power consumption when not using DRV880X. This has invalidated many internal circuits, including internal voltage rails and charge pumps. Nsleep was asserted low. The logic of this input pin causes normal operation. When switching from low to high, the user should allow 1 millisecond delay before applying the PWM signal. The oil supply pump takes this time to stabilize.

Mode 1 (mode on DRV8800)

Input mode 1 is used to switch between fast attenuation mode and slow attenuation mode. The logic is in the mode of slow attenuation.

Mode 2 (only DRV8801)

Mode 2 is used to select which set of drivers (high -voltage and low voltage side) during the slow decline cycle. Only when Mode 1 is asserted to be high, Mode 2 is meaningful. The logic high level of Mode 2 is re -circulated by the high -voltage side drive. Logic low levels circulate current through low -voltage side drives.

braking

The braking function is achieved by driving device (mode 1 pins) in a slow attenuation mode and will be lifted to the low level. Because the DMOS can be driven by the DMOS switch in two directions, as long as the chopping mode is enabled, this configuration effectively makes the BEMF short circuit generated by the motor. The maximum current can be similar to VBEMF/RL. Pay attention to ensure that under the worst brake (high -speed and high -inertia load), it does not exceed the maximum rated value of the device.

Diagnostic output

NFAULT pins indicate that the chip has a problem with the chip through the opening leak output signal. Electric failure, under pressure conditions, or TJ gt; 160 ° C can lead to low pins. This output is invalid when NSLEEP placed the device at the minimum power consumption mode (that is, NSLEEP low). NFAULT maintains an assertion state (nfault L), until VBB reaches VBBNFR, so that the net vacuum of the charge pump reaches its underwriting threshold. NFAULT is a state -limited signal and does not affect any device function. When the H bridge is confirmed to confirm NFAULT, it still works normally under VBB 8 V.

Hot shutdown (TSD)

Two mold temperature monitors are integrated on the chip. When the mold temperature rises to the maximum value, a thermal warning signal will be triggered at 160 ° C. This failure will make NFAULT lower, but it will not make the chip unable to work. If the mold temperature rises further to about 175 ° C, the output of the entire bridge will be disabled until the internal temperature drops to a lag below 15 ° C.

(1), x it doesn't matter, z High impedance

(2), in order to prevent the current reverse in the current in the process of rapid attenuation, when the current is close to 0 A, the output will enter the high impedance state.

Overcurrent protection

Monitor the current flowing through the high -voltage and low -voltage side drives to ensure that the motor wire does not have a short circuit of the power supply or ground. If the short -circuit is detected, the output of the whole bridge is closed, the signal NFAULT is low -level driver, and the 1.2 millisecond fault meter starts. After this 1.2 millisecond time, TOCP, the device is allowed to follow the input command and try another opening (during this attempt, NFAULT becomes higher again). If there is still a failure, the cycle is repeated. If the TOCP expires, there is no short -circuit situation, and normal operation will be resumed and the judgment of NFAULT will be canceled.

Sensory

Low -value resistors can be placed between sensing pins and grounding, for current influenza. In order to make the sensing output current of the current grounding trace IR minimum, the current influenza responder should have an independent grounding circuit to connect to the star ground. This trajectory should be as short as possible. For low -value sensing resistors, the decrease in IR in PCB may be very significant and should be considered.

Note

When selecting the sensor resistance value, the sensing does not exceed the maximum voltage of ± 500 mv. When any current in the motor winding generates an inductive voltage greater than or equal to 500 MV, the H bridge is disabled and enters the cycle.

Equipment function mode

Device operation

DRV880X supports low -power dormant mode through NSLEEP pins. In this mode, the device shuts down most of the internal circuits, including internal voltage rails and charge pumps. Raising the NSLEEP pin will cause the device to restore the state of activity.

During the normal operation, the DRV880X design is used to operate a single -brush DC motor. The output is connected to each side of the motor coil to allow completely two -way control.

Slow attenuation SR (braking mode)

In the slow attenuation mode, the two low -side sink drives are opened, allowing the current to pass through the low side of the H bridge (two sink drives) and the Load cycle. The power consumption of the two receiver DMOS drivers I2R loss:

Synchronize the rapid attenuation of rectification

In this case, the opposite of the decay mode is the switch drive. When fast attenuation, the motor current is not allowed to be negative (direction change). Instead, when the current is close to zero, the driver will be closed. The power calculation is the same as the drive current calculation (see equations 5).

Application and Implementation

Note

The information in the following application chapters is not part of the TI component specification. TI does not guarantee that it is accurate accurateSex 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

The DRV880X device is used to control the DC motor control application.

Typical application

Design requirements

In this design example The parameters are used as the input parameter.

Detailed design program

motor voltage

The motor voltage used depends on the rated value of the selected motor and the required speed. The higher voltage makes the rotation speed of the brushing motor faster, and the same pulse width modulation duty cycle is applied to the power field effect transistor. The higher voltage will also increase the current changes in the current through the inductive motor winding.

Power consumption

DRV880X power consumption is the function of the RMS motor current and the FET resistance (RDS (on)) of each output.

In this example, the ambient temperature is 35 ° C and the knot temperature reaches 65 ° C. At 65 ° C, the sum of RDS (on) is about 1 . If the current of the motor is 0.8A, the power dispersed in the form of heat will be 0.8A2X1 0.64W.

The temperature reached by DRV880X depends on the heat resistance to air and PCB. It is important to welded the device PowerPad to the PCB floor, and the top of the top and bottom plates are connected to spread the heat to the PCB and reduce the temperature of the device. In the example used here, the effective thermal resistance of DRV880X is 47 ° C/W, and:

When the inductive voltage exceeds VTRIP (0.5 V), the current is detected. The size of the RSENSE resistor should set the required ITRIP level.

Set the iTrip to 2.5 a, RSENSE 0.5 v/2.5 a 0.2

To prevent accidental jumping, ITRIP must be higher than the normal working current. Motor current during startup is often much larger than steady -state rotation, because the initial load torque is higher, and no anti -electrocomputer will cause higher voltage and additional currents on the motor winding.

It is useful to limit the start current by using series inductors at the DRV880X output end, because this can reduce ITRIP and may reduce the volume capacitor required by the system. The start -up current can also be limited by increasing the positive driving duty cyclesystem.

Selection of sensing resistance

In order to obtain the best performance, the sensor must be:

Low inductance

The rated power is high enough

near the motor drive

Drive current

This current path is through the high side. Source DMOS driver, motor winding, and low -side sink DMOS driver. The power consumption I2R is lost in a source and a receiver DMOS driver, such as equal 5.

Application curve

Power suggestion

Body capacitor

It is suitable Local volume capacitance 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.

the capacitor of the power supply and its ability to provide current.

Parasitic inductance between the power supply and the motor system.

acceptable voltage ripples.

the type of motor (brush, brushless DC, step motor).

motor 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.

Layout

Layout Guide

Print circuit board (PCB) should use heavy floor floor. In order to obtain the best electrical and thermal performance, the DRV880X must be welded directly to the circuit board. Below DRV880X is a hot pad, which provides a path to enhance heat dissipation. The hot pads should be welded directly on the exposed surface of PCB. The thermal hole is used to pass the heat to other layers of the PCB.

Load power supply foot VBB should be connected parallel with electrolytic capacitors (usually 100 μF) and ceramic capacitors (0.1 μF), as close to the equipment as possible.

Ceramic capacitors (0.1 μF) between VCP and VBB and CP1 and CP2 should be as close to the device as much as possible.

The sensing resistance should be as close to the detection pin and grounding circuit as much as possible to minimize the parasitic inductance.

layout example