Electronic Components Datasheet Search |
|
L6918A Datasheet(PDF) 10 Page - STMicroelectronics |
|
L6918A Datasheet(HTML) 10 Page - STMicroelectronics |
10 / 35 page L6918 L6918A 10/35 DEVICES DESCRIPTION The devices are integrated circuit realized in BCD technology. They provide, in kit, a complete control logic and protections sets for a high performance four-phases step-down DC-DC converter optimized for microprocessors supply and High Density DC-DC converters. They are designed to drive N-Channel mosfets in an interleaved four-phase synchronous-rectified buck topology. Each controller provides a 180 deg phase shift between its two phases and a 90deg phase-shifted synchronization signal is passed from the master to the slave controller that locks the signal through a PLL. The resulting four-phases converter synchronized together results in a 90 deg phase shift on each phase, allowing a consistent reduction of the input capacitors ripple current, minimizing also the size and the power losses. The output voltage of the converter can be precisely regulated, programming the master's VID pins, from 1.100V to 1.850V with 25mV binary steps. The reference for the regulation is passed from the master device to the slave device through apposite pin likewise the synchronization signal. Each device provides an average current-mode control with fast transient response. They include a 300kHz free-running os- cillator externally adjustable up to 600kHz, realized in order to multiply by 4 times the equivalent system fre- quency. The error amplifier features a 15MHz gain-bandwidth product and 10V/ µs slew rate that permits high converter bandwidth for fast transient performances. Current information is read in all the devices across the lower mosfets RDSON or across a sense resistor in fully differential mode. The current information corrects the PWM output in order to equalize the average current carried the two phases of each device. Current sharing between the two phases of each device is then limited at ±10% over static and dynamic conditions. Current sharing between devices is assured by the droop function. The device protects against over-current, with an OCP threshold for each phase, entering in constant current mode. Since the current is read across the low side mosfets, the constant current keeps constant the bottom of the inductors current triangular waveform. When an under voltage is detected the Slave device latches. The Slave device also perform an over voltage protection that disable immediately both devices turning ON the lower driver and driving high the FAULT pin. Over Load condition are transmitted from the Slave device(s) to the master through the SLAVE_OK line. MASTER - SLAVE INTERACTIONS Figure 1. Four Phase connection with L6918 family Master and slave devices are connected together in order to realize four-phase high performance step-down DC/DC converter. Four-phase converter is implemented using L6918A master and one L6918 slave devices as shown in figure 1. A communication bus is implemented among all the controllers involved in the regulation. This bus consists in the following lines: – Reference (VPROG_IN / VPROG_OUT pins): Unidirectional line. The devices share the reference for the regulation. The reference is programmed through the master device VID pins. It exits from the master through the VPROG_OUT pin and enters the slave device through the VPROG_IN pin(s). Filter externally with at least 1nF capacitor. VID 9.0 S YNC_OUT V PROG_OUT SLAV E_OK OS C SYNC_IN V PROG_IN SLAV E_OK OS C S YNC_OUT P GOOD P GOOD |
Similar Part No. - L6918A |
|
Similar Description - L6918A |
|
|
Link URL |
Privacy Policy |
ALLDATASHEET.COM |
Does ALLDATASHEET help your business so far? [ DONATE ] |
About Alldatasheet | Advertisement | Datasheet Upload | Contact us | Privacy Policy | Link Exchange | Manufacturer List All Rights Reserved©Alldatasheet.com |
Russian : Alldatasheetru.com | Korean : Alldatasheet.co.kr | Spanish : Alldatasheet.es | French : Alldatasheet.fr | Italian : Alldatasheetit.com Portuguese : Alldatasheetpt.com | Polish : Alldatasheet.pl | Vietnamese : Alldatasheet.vn Indian : Alldatasheet.in | Mexican : Alldatasheet.com.mx | British : Alldatasheet.co.uk | New Zealand : Alldatasheet.co.nz |
Family Site : ic2ic.com |
icmetro.com |