2 Independent Control

H Bridge

RDS, ON LT; 0.9 @Environmental temperature u003d 25 ° C, vs u003d 14 v

0.8a DC Datamless film

Low static mode IQ LT; 200 μA

Heat Protection

Cross -conduction protection

Power voltage up to 40V

CMOS compatibility Input

Output short -circuit protection

Instructions

L9925 is the application of Shuangquan Bridge drive motor application of the stepper motor. In BCD (bipolar, CMOS AMP; AMP; DOS) technology, logic circuit, precision linear block and power transistor combination together optimize the performance of the circuit and minimize the chip component. Schmidt trigger is used for all input levels and completely compatible 5VCMOS logic levels. When both enable signals are low, the IC is commanded to enter the low static current state, from the battery. The charge pump is integrated on the chip; no external components are required. Give full play to maintaining 9V lt; vs lt; 16V. Expansion range 6V lt; vs lt; 9V and 16V lt; vs lt; 40V, complete functions, but easy performance. The ultra -temperature protection of all pins and ESD protection ensure reliability and reduce the failure of the system.

Absolute maximum rated value

The absolute maximum fixed value refers to the value that may cause damage to the device that may cause the device. The operation of functionality is not implicit. For the voltage and current applied outside the device:

(1) If the pulse and short circuit appear at the same time at one or more outputs, the device may be excessively stressful.

Electrical features (vs u003d 9 to 16V; TJ u003d -40 to 150 ° C (3), unless there are other regulations.)

When current is current When inflowing the pin, refer to the voltage and current of GND.

(3) Test at the temperature of 125 ° C, and pass the correlation coefficient of 150 ° C to ensure parameters

General operation

] After enabling the network bridge, each input inx is directly mapped to the corresponding output OUTX. The output voltage will be equal to the load current between the supply chain and the product between the supply chain and the product. VOUT u003d V power- (RDS, on #8901; ILOAD). The source load current is positive.

FIGDC motor driver. In order to ensure the safety of the circuit during the reverse work of the battery, the reverse protection diode D1 needs to be used. The transient protection diode D2 must ensure that the power supply voltage VSVBAT row during the transient period will be limited to the absolute maximum rated value of less than VVSP. The capacity CB is used to reduce VS-EMR, and its value depends on the driver load. The resistance feedback circuit is connected to the μP power line through the diode DO to allow the opening of the load detection. Protective device output resistance EMI or ESD GT; 2KV external capacitor CEX.

Circuit description

L9925 is a dual -full bridge integrated circuit used to drive DC motors, step motors and other inductive motor loads. The EAH bridge has 4 power DMOS transistors RDSON u003d 0.75 and relative protection and control circuits (see Figure 5). The four -quarter bridge of T can independently control the four input methods of IN1, IN3, IN4 and 2 through the following ways to entered enable1 and enable2.

Cross -conductors

This device is observed by observing the internal grid polar voltage to ensure that there is no cross -conductive power vehicle manufacturer. The transistor operation is open. When a power DMOS transistor can be regarded as a resistor RDS (on) u003d 0.75 connection temperature is 25 ° C. In this case, it generates dispersing power through the following ways: PON u003d RDS (Open) #8901; IDS2's low RDS (on) of the multi -power BCD process can provide low -power high current.

Close status

When one of the power DMOS transistors turn off VDS voltage equal to the power supply voltage, only leakage current IDSS flows. Gives the power consumption during this period: POFF u003d vs #8901; IDSS

Transition

Like all MOS power transistors An internal diode, it can be used as a fast -flow diode in the switch mode application. In the process of re -cycle, the enable input is low, the power MOS is closed, and the diode voltage is fixed in its characteristics. When the input is low, the power MOS is closed, and the diode carries all the receiving current. The power consumed within the cycle conversion time depends on the voltage and current waveform in the application. Ptrans u003d IDS (T) #8901; VDS (T)

Heat protection

Including a heat protection circuit, if the temperature is lower than the temperature decreases, With the control of the input and enable signal of 150 ° C, the device is restarted to the safe level.

Application information

Circulation

Enter high on enalbe and followDuring the ring, the voltage on the transistor was reduced to RDS. For voltage less than 0.6V, and holding the voltage depends on a higher voltage of the diode. Although the device has protection measures to prevent cross -conductors. In order to achieve the high performance provided by the power consumption of the bridge to L9925, it must be noted that it has enough PCB area to dissipate heat. The first stage of any heat design is calculation applications. In this example, consider the half -step operation shown in Figure 6. When the rising time TR is opened, the current begins to flow in the inductive load until the maximum current IL reaches the time TR, that is, the dispersion energy EOFF/on.

on time to ton

During this period, energy dissipation is due to the transistor EON and the reduction economy. As the two power DMO crystal pipes, EON is connected by the following formulas: EON u003d IL2 #8901; RDS (open) #8901; 2 #8901; : Economy u003d vs #8901; IL #8901; TCOM #8901; F switch #8901; ton

tCOM u003d communication time, assuming: tCOM u003d Trise u003d tFall ≤20 μs T switch u003d chop frequency decrease time decrease time In this example, TF assumes that the energy dissipates in this part of the cycle and take the same ascending time as follows:

Static energy

The energy consumption of energy dissipation The last contribution is due to static power supply current and: equivalent u003d iQuiescent #8901; vs #8901; t

Each cycle total energy

etot u003d (2 #8901; eOFF/On+EON+ ECOM）桥接1+

+（2 #8901;EOFF/ON+EON+ECOM）bridg2+等分

总功耗PDI简单地说：

[123 ] TR u003d rise

ton u003d on time

tf u003d drop time

toff u003d closing time

t u003d cycle

t u003d TR+TON+TF+TOFF