BA6901F

Motor driver ICs

6/10

•CL, CS, CNF terminal

Output current is limited by voltage (VCL) that inputting to the CL terminal.

Resistor (RNF) of the output current detection is connected between emitter of the external output transistor and GND,

and output current is detected by inputting the voltage which occurred in that resistor to the CS terminal. Output current

is restricted as the electric potentials of the CL and the CS terminals are equal. But, there is offset between the CL

terminal and the CS terminal. Value of current limit is found by the following equation.

Value of current limit

=

RNF

VCL

−VCL_CSofs

VCL_CSofs : Offset between CL terminal and CS terminal

This offset is not the one written at electrical characteristics table, but the value determined under condition that the

external output transistors are connected. Be careful of this value, because it varies according to the external transistor.

The lager hFE of the output transistor makes the offset smaller, and smaller hFE makes it larger.

needed.

However, when an output current limit isn’t needed, CS terminal is fixed on the low level (GND), and CL terminal is fixed

CNF

A1

A2

CS

CL

Current limit

(a) In the case that the current limit is applied.

CNF

A1

A2

CS

CL

(b) In the case that the current limit isn't applied.