3PHASEPWM Datasheet, PDF (3/5 Pages) International Rectifier – 3-Phase Synchronous PWM Controller IC Provides an Integrated Solution for Intel VRM 9.0 Design Guidelines

Figure 1 – Typical application of IRU3055
The IRU3055 has on-board MOSFET drivers,
making it cost-effective compared to the
majority of multiphase controllers, which
require external MOSFET drivers. When used
with IR’s HEXFET^® power MOSFETs like the
IRF3704S in the control FET socket and the
IRF3711S in the synchronous FET socket, the
IRU3055 can provide up to 60A for
microprocessor V_CORE requirements at 80%
efficiency or above.
The new controller IC is a fixed-frequency
voltage mode controller with 50kHz to 500kHz
programmable operating frequency by using an
external resistor. The output voltage is selectable
in 25mV steps from 1.075 to 1.85V with up to
1.5% output voltage accuracy using a
programmable VID code to the five-bit digital-
to-analog converter (DAC).
The new device has a number of features to
provide protection and monitoring for the power
system and the microprocessor. It features
under-voltage lockout (UVLO) for the 5V and
12V supplies as well as an externally
programmable soft-start function. Another
feature is the PGOOD monitor circuit, which is
held low if the output of the converter is not
within ±10% of the programmed voltage.
The IRU3055 also provides over-voltage
protection. If the output voltage exceeds the
DAC-programmed voltage by 20%, the low-side
MOSFETs turn on and shunt the output voltage
to ground, protecting the CPU from damage.
The IRU3055 features loss-less inductor current
sensing and sharing while over-current
protection is achieved by synchronous FET
R_DS(on) sensing, eliminating the need for a
separate sense resistor. The IRU3055 can also be
easily configured for voltage droop
compensation so that the output voltage will
linearly decrease as load current increases and
vice versa, as required by Intel VRM design
guidelines.
3