PDF《CPUs》

LM2633 www.

ti.com SNVS139C CMAY 2004CREVISED APRIL

2005 LM2633 Advanced Two-Phase Synchronous Triple Regulator Controller for Notebook CPUs Check for Samples: LM2633 1FEATURES ? Programmable output UVP delay 23GENERAL ? 250kHz switching frequency (for Vin <

17V) ? Channel

1 output from 0.925V to 2.00V ? Three regulated output voltages ? ±1.5% DAC accuracy from 0°C to 125°C ? 4.5V to 30V input range ? ±1.7% initial tolerance for Channel

2 ? Power good function ? Dynamic VID change ready ? Input under-voltage lockout ? Power good flags VID changes ? Thermal shutdown ? Channel

2 output from 1.3V to 6.0V ? Tiny TSSOP package LINEAR SECTION SWITCHING SECTION ? Output voltage adjustable ? Two channels operating 180° out of phase ? 50mA maximum driving current ? Separate on/off control for each channel ? Output UVP ? Current mode control without sense resistor ? ±2% initial tolerance ? Skip-mode operation available ? Adjustable cycle-by-cycle current limit APPLICATIONS ? Negative current limit ? Power supply for CPUs of notebook PCs that ? Analog soft start independent of input voltage require the SpeedStep? technique slew rate ? Power supply for information appliances ? Power ground pins separate ? General low voltage DC/DC buck regulators ? Output UVP and OVP DESCRIPTION The LM2633 is a feature-rich IC that combines three regulator controllers - two current mode synchronous buck regulator controllers and a linear regulator controller. The two switching regulator controllers operate 180° out of phase. This feature reduces the input ripple RMS current, resulting in a smaller input filter. The first switching controller (Channel 1) features an Intel mobile CPU compatible precision 5-bit digital-to-analog converter which programs the output voltage from 0.925V to 2.00V. It is also compatible with the dynamic VID requirements. The second switching controller (Channel 2) is adjustable between 1.25V to 6.0V. Use of synchronous rectification and pulse-skip operation at light load achieves high efficiency over a wide load range. Fixed-frequency operation can be obtained by disabling the pulse-skip mode. Current-mode feedback control assures excellent line and load regulation and a wide loop bandwidth for good response to fast load transient events. Current mode control is achieved through sensing the Vds of the top FET and thus an external sense resistor is not necessary. A power good signal is available to indicate the general health of the output voltages. A unique feature is the analog soft-start for the switching controllers is independent of the slew rate of the input voltage. This will make the soft start behavior more predictable and controllable. An internal 5V rail is available externally for boot-strap circuitry (only) when no 5V is available from other sources.

1 Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet. 2SpeedStep is a trademark of dcl_owner. 3All other trademarks are the property of their respective owners. PRODUCTION DATA information is current as of publication date. Copyright ? 2004C2005, Texas Instruments Incorporated Products conform to specifications per the terms of the Texas Instruments standard warranty. Production processing does not necessarily include testing of all parameters. LM2633 SNVS139C CMAY 2004CREVISED APRIL

2005 www.ti.com Current limit for either of the two switching channels is achieved through sensing the top FET VDS and the value is adjustable. The two switching controllers have under-voltage and over-voltage latch protections, and the linear regulator has under-voltage latch protection. Under-voltage latch can be disabled or delayed by a programmable amount of time. The input voltage for the switching channels ranges from 5V to 30V, which makes possible the choice of different battery chemistries and options. Connection Diagram TOP VIEW Figure 1. 48-Lead TSSOP (MTD) Pin Functions Pin Descriptions FB1 (Pin 1):The feedback input for Channel 1. Connect to the load directly. COMP1 (Pin 2): Channel