TMP814

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SLDS151A – MAY 2009 – REVISED JUNE 2015

Feature Description (continued)

7.3.2 Constant Voltage Bias

Constant Voltage Bias is provided through VOVER Pin. This must be used for applications of 24 V and 48 V.

when not in use.

7.3.3 Soft-Start

Soft-Start Time can be using the ROFF pin. Connect 6 to 6VREG is not used.

7.3.4 Lock Detection

When the rotor is locked by external means or load conditions, The lock detection feature helps to protect the

circuit by not allowing the current to rise beyond control. A hiccup mechanism is also provided. The lock

detection is enabled by a connection to the lock detection capacitor. When the pin voltage rises to 1.2 V, the

constant current charge and discharge circuits cause the drive to and enables it back when voltage reaches 0. If

lock detection feature is not desired in the application, then this pin must be connected to ground.

7.3.5 Current Limit

Current limit resistor is connected in a return path of H Bridge connection. This input is connected to the SENSE

pin where the Current is limited when the voltage across this resistor crosses the voltage at VLIM Pin. If not

used, this pin needs to be connected to ground.

7.3.6 Minimum Speed Setting

Minimum speed setting feature is used with the RMI pin in the device. Connect to 6VREG with a pullup resistor if

not used.

7.3.7 Speed Output

The speed of the motor while running can be observed at the FG pin which is an open collector output and

needs to be pulled high for using it.

7.3.8 Drive Frequency Selection

The P channel switches in the device are switched with higher frequency whose duty cycle is decided by the

speed control input. The frequency of the operation can be decided by the capacitor connected at the CPWM

pin. As this is used also for the current limiting canceling signal, be sure to connect the capacitor even when

speed control is not used.

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