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參數(shù)資料
| 型號： | RC5058M |
| 廠商： | FAIRCHILD SEMICONDUCTOR CORP |
| 元件分類： | 穩(wěn)壓器 |
| 英文描述： | Current-Mode SMPS Controller |
| 中文描述： | SWITCHING CONTROLLER, 345 kHz SWITCHING FREQ-MAX, PDSO24 |
| 封裝： | SOIC-24 |
| 文件頁數(shù)： | 12/18頁 |
| 文件大?。?/td> | 257K |
| 代理商： | RC5058M |
RC5058
PRODUCT SPECIFICATION
12
REV. 1.0.0 6/30/00
Test Parameters
Figure 3. Ouput Drive Timing Diagram
Application Information
The RC5058 Controller
The RC5058 is a programmable synchronous DC-DC con-
troller IC. When designed around the appropriate external
components, the RC5058 can be configured to deliver more
than 16A of output current, as appropriate for the Katmai and
Coppermine and other processors. The RC5058 functions as
a fixed frequency PWM step down regulator.
Main Control Loop
Refer to the RC5058 Block Diagram on page 1. The RC5058
implements “summing mode control”, which is different from
both classical voltage-mode and current-mode control. It
provides superior performance to either by allowing a large
converter bandwidth over a wide range of output loads.
The control loop of the regulator contains two main sections:
the analog control block and the digital control block. The
analog section consists of signal conditioning amplifiers feeding
into a comparator which provides the input to the digital control
block. The signal conditioning section accepts input from the
DROOP (current feedback) and VFB (voltage feedback) pins
and sets up two controlling signal paths. The first, the voltage
control path, amplifies the difference between the VFB signal
and the reference voltage from the DAC and presents the
output to one of the summing amplifier inputs. The second,
current control path, takes the difference between the DROOP
and SW pins when the high-side MOSFET is on, reproducing
the voltage across the MOSFET and thus the input current; it
presents the resulting signal to another input of the summing
amplifier. These two signals are then summed together. This
output is then presented to a comparator looking at the oscillator
ramp, which provides the main PWM control signal to the
digital control block.
The digital control block takes the analog comparator input
and the main clock signal from the oscillator to provide the
appropriate pulses to the HIDRV and LODRV output pins.
These two outputs control the external power MOSFETs.
There is an additional comparator in the analog control section
whose function is to set the point at which the RC5058 current
limit comparator disables the output drive signals to the
external power MOSFETs.
High Current Output Drivers
The RC5058 contains two identical high current output drivers
that utilize high speed bipolar transistors in a push-pull config-
uration. The drivers’ power and ground are separated from
the chip’s power and ground for switching noise immunity.
The power supply pin, VCCP, is supplied from an external
12V source through a series 33
resistor. The resulting volt-
age is sufficient to provide the gate to source drive to the
external MOSFETs required in order to achieve a low R
DS,ON
.
Internal Voltage Reference
The reference included in the RC5058 is a precision band-gap
voltage reference. Its internal resistors are precisely trimmed
to provide a near zero temperature coefficient (TC). Based on
the reference is the output from an integrated 5-bit DAC. The
DAC monitors the 5 voltage identification pins, VID0-4. When
the VID4 pin is at logic HIGH, the DAC scales the reference
voltage from 2.0V to 3.5V in 100mV increments. When VID4
is pulled LOW, the DAC scales the reference from 1.30V to
2.05V in 50mV increments. All VID codes are available, includ-
ing those below 1.80V.
Power Good (PWRGD)
The RC5058 Power Good function is designed in accordance
with the Pentium II and III DC-DC converter specifications
and provides a continuous voltage monitor on the VFB pin.
The circuit compares the VFB signal to the VREF voltage
and outputs an active-low interrupt signal to the CPU should
the power supply voltage deviate more than ±12% of its
nominal setpoint. Power Good outputs an open collector
high when the output voltage is within ±8% of its nominal
setpoint. The Power Good flag provides no other control
function to the RC5058.
Output Enable/Soft Start (ENABLE/SS)
The RC5058 will accept an open collector/TTL signal for
controlling the output voltage. The low state disables the output
voltage. When disabled, the PWRGD output is in the low state.
Even if an enable is not required in the circuit, this pin should
have attached a capacitor (typically 100nF) to softstart the
switching. A larger value may occasionally be required if the
converter has a very large capacitor at its output.
Over-Voltage Protection
The RC5058 constantly monitors the output voltage for protec-
tion against over-voltage conditions. If the voltage at the VFB
pin exceeds the selected program voltage, an over-voltage
condition is assumed and the RC5058 disables the output
drive signal to the external high-side MOSFET. The DC-DC
converter returns to normal operation after the output voltage
returns to normal levels.
Oscillator
The RC5058 oscillator section uses a fixed frequency of
operation of 300KHz.
t
R
5V
t
DT
t
DT
t
F
HIDRV
to SW
LODRV
2V
2V
2V
5V
2V
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| RC5058MT | 功能描述:開關(guān)變換器、穩(wěn)壓器與控制器 SOIC-24 RoHS:否 制造商:Texas Instruments 輸出電壓:1.2 V to 10 V 輸出電流:300 mA 輸出功率: 輸入電壓:3 V to 17 V 開關(guān)頻率:1 MHz 工作溫度范圍: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:WSON-8 封裝:Reel |
| RC5060 | 制造商:FAIRCHILD 制造商全稱:Fairchild Semiconductor 功能描述:ACPI Switch Controller |
| RC5060M | 功能描述:開關(guān)變換器、穩(wěn)壓器與控制器 SOIC-20 RoHS:否 制造商:Texas Instruments 輸出電壓:1.2 V to 10 V 輸出電流:300 mA 輸出功率: 輸入電壓:3 V to 17 V 開關(guān)頻率:1 MHz 工作溫度范圍: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:WSON-8 封裝:Reel |
| RC5060MT | 功能描述:開關(guān)變換器、穩(wěn)壓器與控制器 SOIC-20 RoHS:否 制造商:Texas Instruments 輸出電壓:1.2 V to 10 V 輸出電流:300 mA 輸出功率: 輸入電壓:3 V to 17 V 開關(guān)頻率:1 MHz 工作溫度范圍: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:WSON-8 封裝:Reel |
| RC5061 | 制造商:FAIRCHILD 制造商全稱:Fairchild Semiconductor 功能描述:High Performance Programmable Synchronous DC-DC Controller for Multi-Voltage Platforms |
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