IFX91041 Ver la hoja de datos (PDF) - Infineon Technologies

Número de pieza

componentes Descripción

Fabricante

IFX91041

1.8A DC/DC Step-Down Voltage Regulator 5.0V, 3.3V or Adjustable Output Voltage

Infineon Technologies 

IFX91041

Module Oscillator

7

Module Oscillator

7.1

Description

The oscillator turns on the power switch with a constant frequency while the buck regulating circuit turns the power

transistor off in every cycle with an appropriate time gap depending on the output and input voltage.

The internal sawtooth signal used for the PWM generation has an amplitude proportional to the input supply

voltage (feedforward).

The turn-on frequency can optionally be set externally via the ’SYNC’ pin using a TTL compatible input signal. In

this case the synchronization of the PWM-on signal refers to the falling edge of the ’SYNC’-pin input signal. In case

the synchronization to an external clock signal is not needed the ’SYNC’ pin should be connected to GND.

Leaving pin SYNC open or short-circuiting it to GND leads to normal operation with the internal switching

frequency.

7.2

Electrical Characteristics Module Oscillator

Electrical Characteristics: Buck Regulator

VS = 6.0 V to 40 V, Tj = -40 °C to +125 °C, all voltages with respect to ground (unless otherwise specified)

Pos. Parameter

Symbol

Limit Values

Unit Conditions

Min. Typ. Max.

7.2.1 Oscillator frequency

fosc

330

370

420

kHz VSYNC = 0V

7.2.2 Synchronization capture range

fsync

200

530 kHz

7.2.3

7.2.4

SYNC signal high level valid

SYNC signal low level valid

VSYNC,hi 2.9

VSYNC,lo

V

1)

0.8

V

1)

7.2.5 SYNC input internal pull-down

RSYNC

0.60 1.0

1.4

MΩ VSYNC = 5V

1) Synchronization of PWM-on signal to falling edge.

Data Sheet

11

Rev. 1.02, 2010-02-23

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