MC34164-3 Datasheet, PDF(12/23 Page) Freescale Semiconductor, Inc – 3.0 A 1.0 MHz Fully Integrated DDR Switch-Mode Power Supply

English

English German Russian Spanish Italian Polish Chinese Japanese Korean French Portuguese	Language :

MC34164-3 Datasheet, PDF (12/23 Pages) Freescale Semiconductor, Inc – 3.0 A 1.0 MHz Fully Integrated DDR Switch-Mode Power Supply

◁

FUNCTIONAL DESCRIPTION

FUNCTIONAL INTERNAL BLOCK DESCRIPTION

Internal Bias

Circuits

System Control

& Logic

Oscillator

Protection

Functions

Control &

Supervisory

Functions

Tracking &

Sequencing

Buck Converter

Figure 5. 34712 Internal Block Diagram

INTERNAL BIAS CIRCUITS

This block contains all circuits that provide the necessary

supply voltages and bias currents for the internal circuitry. It

consists of:

â¢ Internal Voltage Supply Regulator: This regulator

supplies the VDDI voltage that is used to drive the digital/

analog internal circuits. It is equipped with a Power-On-

Reset (POR) circuit that watches for the right regulation

levels. External filtering is needed on the VDDI pin. This

block will turn off during the shutdown mode.

â¢ Internal Bandgap Reference Voltage: This supplies the

reference voltage to some of the internal circuitry.

â¢ Bias Circuit: This block generates the bias currents

necessary to run all of the blocks in the IC.

SYSTEM CONTROL AND LOGIC

This block is the brain of the IC where the device

processes data and reacts to it. Based on the status of the

STBY and SD pins, the system control reacts accordingly and

orders the device into the right status. It also takes inputs

from all of the monitoring/protection circuits and initiates

power up or power down commands. It communicates with

the buck converter to manage the switching operation and

protects it against any faults.

OSCILLATOR

This block generates the clock cycles necessary to run the

IC digital blocks. It also generates the buck converter

switching frequency. The switching frequency has a default

value of 1.0 MHz and can be programmed by connecting a

resistor divider to the FREQ pin, between VDDI and GND

pins (See Figure 1).

PROTECTION FUNCTIONS

This block contains the following circuits:

â¢ Over Current Limit and Short Circuit Detection: This

block monitors the output of the buck converter for over

current conditions and short circuit events and alerts the

system control for further command.

â¢ Thermal Limit Detection: This block monitors the

temperature of the device for overheating events. If the

temperature rises above the thermal shutdown

threshold, this block will alert the system control for

further commands.

â¢ Output Overvoltage and Undervoltage Monitoring: This

block monitors the buck converter output voltage to

ensure it is within regulation boundaries. If not, this

block alerts the system control for further commands.

CONTROL AND SUPERVISORY FUNCTIONS

This block is used to interface with an outside host. It

contains the following circuits:

â¢ Standby Control Input: An outside host can put the

34712 device into standby mode (S3 or Suspend-To-

RAM mode) by sending a logic â0â to the STBY pin.

â¢ Shutdown Control Input: An outside host can put the

34712 device into shutdown mode (S5 or Suspend-To-

Disk mode) by sending a logic â0â to the SD pin.

â¢ Power Good Output Signal PG: The 34712 can

communicate to an external host that a fault has

34712

Analog Integrated Circuit Device Data

Freescale Semiconductor

▷