Rainbow-electronics ATA6824 Manual de usuario descargar pdf (Pagina 10)

4931C–AUTO–09/06

ATA6824 [Preliminary]

5.5 Control Inputs DIR and PWM

5.5.1 Pin DIR

Logical input to control the direction of the external motor to be controlled by the IC. An internal

pull-down resistor is included.

5.5.2 Pin PWM

Logical input for PWM information delivered by external microcontroller. Duty cycle and fre-

quency at this pin are passed through to the H-bridge. An internal pull-down resistor is included.

The internal signal ON is high when

• At least one valid trigger has been accepted (SYNC = 1)

•V

BAT

is inside the specified range (UV = 0 and nOV = 1)

• The charge pump has reached its minimum voltage (CPOK = 1) and

• The device is not overheated (OT2 = 0)

In case of a short circuit, the appropriate transistor is switched off after a debounce time of about

10 µs. In order to avoid cross current through the bridge, a cross conduction timer is imple-

mented. Its time constant is programmable by means of an RC combination.

Table 5-1. Status of the IC Depending on Control Inputs and Detected Failures

Control Inputs Driver Stage for External Power MOS Comments

ON DIR PWM H1 L1 H2 L2

0 X X OFF OFF OFF OFF Standby mode

1 0 PWM ON OFF /PWM PWM Motor PWM forward

1 1 PWM /PWM PWM ON OFF Motor PWM reverse

Table 5-2. Status of the Diagnostic Outputs

Device Status Diagnostic Outputs Comments

CPOK OT1 OV UV SC DG1 DG2 DG3

0 X X X X – 1 – Charge pump failure

X 1 X X X – – 1 Overtemperature warning

X X 1 X X – 1 – Overvoltage

X X X 1 X – 1 – Undervoltage

X X X X 1 1 – – Short circuit

Note: X represents: don't care – no effect)

OT1: Overtemperature warning

OV: Overvoltage of VBAT

UV: Undervoltage of VBAT

SC: Short circuit

CPOK: Charge pump OK

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Rainbow-electronics ATA6824 Manual de usuario Pagina 10