Features

H bridge motor driver alone

- Drive DC motor or other load

- Low RDS (on) MOSFET (a typical value of 0.4Ω Ω )

Low-power sleep mode

support 100%PWM

8-38-v working power supply voltage range [ 123]

thermal enhancement surface installation component

can be configured with current limit

protection function

--vbb IOU Lock (UVLO)

- Charging pump IOlight (CPUV)

- Over current protection (OCP)

- Power short circuit protection (STS)

[

[ 123] -Cofi Short -circuit Protection (STG)

- Excessive warning (OTW)

- ultra -temperature stop (OTS)

- 123]

Application

Printer

Industrial automation

Robotics

#8226 ; Electric leverage

Explanation

DRV8816

provides a multi-functional power driver solution with two independent #189; -Hh bridge drivers. This device can drive a winding of a DC motor or a step motor, or it can also drive other devices such as solenoid valves. A simple INX/ENX interface can easily connect to the controller circuit.

The output level is configured with n-channel power MOSFET with #189; -H bridge. The peak output current of DRV8816 can reach ± 2.8A, and the working voltage is as high as 38V. 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.

Internal protection functions can be used for UVLO, charge pump failure, OCP, short -circuit protection of power supply, short -circuit protection, overheating warnings and ultra -temperature stops. The failure state is instructions through the NFAULT pin.

DRV8816 is packaged in a 16 -pin HTSSOP package with PowerPad #8482;

Equipment information

(1) For all available software packages, please refer to the appointment appendix at the end of the data table.

Simplified schematic diagram

Typical features

Detailed description

] Overview DRV8816 uses 4 CMOS inputs to control 2 high -voltage large current outputs, and at the same time integrate protection functions, fault reports, dormant mode and current influenza. According to Table 2, EN1 and IN1 control OUT1, EN2 and IN2 control OUT2. The device is designed to drive two independent loads or one with a brushing electric motor, as shown in Figure 4 and Table 3.

When the RSENSE resistor is used, if the VSENSE exceeds 500 millivoltors, DRV8816 will automatically disable, which provides a user -programmed over -current threshold. VPROPI output is equivalent to 5 times the sensing voltage of 5 times. Micro controls can use it to understand the electric current, thereby performing pulse width modulation of the DRV8816 input and adjusting the motor current.

Figure Figure

Function description

Bridge control

DRV8816 through each #189; -H bridge Control and input pins alone.

Table 2 shows the logic of DRV8816.

If a DC motor is connected to DRV8816, it is connected between OUT1 and OUT2 pins, as shown in Figure 4. Two DC motors can also be connected to DRV8816. In this mode, it is impossible to reverse the direction of the motor; the motor can only rotate in one direction. The connection is shown in Figure 4.

Table 3 shows how to control the operation of the motor of the single -brushed DC motor.

(1), the semi -H bridge is independent, and the output state depends on ENX and INX.

Table 4 shows how to control the motor operation of the dual -brushing DC motor.

The oil supply pump

The charge pump is used to generate a power supply higher than the 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 -chip capacitor is connected between VCP and VBB as a energy storage device to run high -end DMOS devices. The VCP voltage level is monitored by internal monitoring, and the output of the device will be disabled under failure.

vpropi

VPROPI output approximately equal detection quotes5 times the voltage on the feet. VPROPI only makes sense only when a resistor is connected to the Sense pin; if Sense is connected to the ground, VPROPI measures 0 V. It should also be noted that during the slow attenuation (braking) period, VPROPI measured 0 V. Vpropi can output a maximum of 2.5 V because the H bridge was disabled at 500 MV.

Protective circuit

DRV8816 has comprehensive protection, which can prevent VBB owed pressure, charge pump pressure, over -current and overheating events.

VBB UVLO

If the voltage on the VBB pin is lower than the UVLO threshold voltage at any time, all the FET in the H bridge will be disabled and the charge pump will be disabled. When VBB is higher than the UVLO threshold, the operation will be restored. Note that NFAULT does not mean UVLO, because the CPUV failure is always asserted below VBB 12V.

VCP UVLO (CPUV)

During the CPUV incident, the VCP voltage measurement value was lower than VCP+10 V. If the voltage on the VCP pin is lower than the UVLO threshold at any time, the NFAULT pin is driven to a low level. After recovery, the NFAULT pin will be released. Note that the fault will not fail the output FET and allow the device to continue to run. When VBB is lower than 12 V, this failure state is always asserted and NFAULT is pulled down.

OCP

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, all the fets in the H bridge will be disabled, the NFAULT is driven to a low level, and the TOCP fault timer starts. After this period of time, TOCP, the device will be 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 the normal operation will be resumed and the failure is released.

OTW

If the mold temperature rises exceeding the thermal warning threshold, the NFAULT pin drive is low. When the temperature of the mold drops below the lag, the NFAULT pin is released. If the mold temperature continues to rise, the device will enter the overheating shutdown state described in OTS.

OTS

If the mold temperature exceeds the safety limit, all FETs in the H bridge will be disabled and the charge pump will be closed. After the mold temperature drops to the safe level, the operation will be automatically recovered.

Equipment function mode

Sensory

Low -value resistors can be placed between sensing pins and grounding, for current influenza. The design of the printing circuit board should be wide on each side of the resistorThe metal path is to minimize IR decreases that will reduce the detection accuracy. Similarly, the distance from sensors to DRV8816 and large -capacity capacitors should be minimized.

Set a manual over -current check threshold, and place a resistor between the detection pin and GND. When the induction pin rises to more than 500 millions, the H bridge output is disabled (high Z). The device will be automatically tried during TOCP. Overrip threshold can be calculated using itRip 500 mv/ω. The selected over -current checking level cannot be greater than IOCP.

If the sensing resistance is not used, the sensing pins are directly connected to the GND; in this case, the current FET current IOCP detection still plays a role.

Application and implementation

Note

The information in the following application chapters is not part of the TI component specification. 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

DRV8816 is usually used to drive a DC motor.

Typical application

Design requirements

Table 5 shows the parameters to be considered when designing.

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

The power consumption of DRV8816 is the function of the RMS motor current and the FET resistance of each output (RDS (open)).

For example, the ambient temperature is 65 degrees Celsius. In the case of 0.8A, the power dispersed in the form of heat will be 0.8A2X 1 #8486; 0.64W.

The temperature reached by DRV8816 depends on the heat resistance to air and PCB. It is important to welded the device PowerPad to the PCB ground layer, and the top of the top and bottom plates can be used to disperse the heat to the PCB and reduce the temperature of the device. In the example used here, the effective thermal resistance of DRV8816 is 47 ° C/W, and:

When the induction voltage exceeds VTRIP (0.5V), the current is detected. RSEThe size of the NSE resistor should be able to set the required ITRIP level.

Set the iTrip to 2A, RSENSE 0.5V/2A 0.25 #8486;

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 DRV8816 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 driver's duty cycle.

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

The power consumption of sensor resistance is equal to IRMS2X R. For example, if the current of the motor is 3A, the current -per square motor current is 2A, and the sensor of 0.05 #8486; the resistor will consume 2A2X 0.05 #8486; 0.2W. With the rise of current levels, power increases rapidly.

The resistor usually has a rated power within certain ambient temperature range, and the reduction of power curve at high ambient temperature. When a PCB is shared with other heating elements, the balance should be increased. It is best to measure the actual sensing resistance temperature and power MOSFET in the final system, because they are usually the hottest components.

Since the power resistor is larger and more expensive than the standard resistor, multiple standard resistors are usually used between sensing nodes and grounding. This can allocate current and heat dissipation.

Application curve

Power suggestion

Volume capacitance

A suitable local volume capacitor is the motor of the motor An important factor in the design of the driving 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. capacitance and ability to provide current.

Parasitic inductance between the power supply and the motor system.

acceptable voltage ripples.

The type of motor used (there is a DC, 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.

Power Director

Control the input NSLEEP to minimize power consumption when not using DRV8816. 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.

Layout

Layout Guide

Print circuit board (PCB) shall use heavy floor floor. In order to obtain the best electrical and thermal performance, DRV8816 must be welded directly to the circuit board. Below DRV8816 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.

The load power supply foot VBB should be connected parallel with electrolytic capacitors (usually 100 μF), and connects with ceramic capacitors closer to the device as possible. Between VCP and VBB, ceramic capacitors connected to VREG and ceramic capacitors between CP1 and CP2 should be as close to the pin of the device as much as possible to reduce the inductance inductance.

In the formula

PTOT is the total power consumption.

RDS (ON) is a resistor of HS and LS FET.

IOUT (RMS) is an RMS output current applied to each winding.

The rated voltage of a large capacitor should be higher than the operating voltage in order to provide the maneuverability when the motor transmits energy to the power supply.

IOUT (RMS) is equal to 0.7 × full marking output current settings.

The maximum power consumed in the device depends on the ambient temperature and heat dissipation.

Note that RDS (on) increases as the temperature increases, so when the device is heated, the power consumption will increase.

ground

The ground power aircraft should be as close to DRV881 as possible as possible6.The copper connection layer is directly under the hot pad, and the location is very good.Then you can connect this pad to the ground.

layout example

Hot protection

If the mold temperature exceeds 150 ° C, the device will be disabled until the temperature drops to safetyLevel.Any trend of the equipment entering the heat stop indicates that the power consumption is too large, the heat dissipation is insufficient, or the ambient temperature is too high.