Microchip Technology MCP19035 Manual
Microchip Technology MCP19035 Manual

Microchip Technology MCP19035 Manual

High-speed synchronous buck controller
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High-Speed Synchronous Buck Controller
Features:
• Input Voltage Range: from 4.5V to 30V
• Targeted for Low-Voltage Power Trains with
Output Current up to 20A
• High-Speed Voltage Mode, Analog Pulse-Width
Modulation Control
• Power Good Output
• Internal Oscillator, Reference Voltage and
Overcurrent Limit Threshold for Stand-Alone
Applications.
• Multiple Switching Frequency Options (F
- 300 kHz
- 600 kHz
• Integrated Synchronous MOSFET Drivers
• Multiple Dead-Time Options
• Internal Blocking Device for Bootstrap Circuit
• Integrated Current Sense Capability for Short
Circuit Protection
• Internal Overtemperature Protection
• Under Voltage Lockout (UVLO)
• Integrated Linear Voltage Regulator
• 10-LD 3 X 3 mm DFN Package
Applications:
• Point of Loads
• Set-Top Boxes
• DSL Cable Modems
• FPGA's/DSP's Power Supply
• PC's Graphic/Audio Cards
 2012-2013 Microchip Technology Inc.
General Description
The MCP19035 is an application-optimized, high-
speed synchronous buck controller that operates from
input voltage sources up to 30V. This controller
implements a voltage-mode control architecture with a
fixed switching frequency of 300 kHz or 600 kHz. The
high-switching frequency facilitates the use of smaller
passive components, including the inductor and
input/output capacitors, allowing a compact, high-
performance power supply solution. The MCP19035
implements an adaptive anti-cross conduction scheme
):
to prevent shoot-through in the external power
SW
MOSFETs. Furthermore, the MCP19035 offers multiple
dead-time options, enabling an additional degree of
optimization, allowing a higher efficiency power supply
design.
The MCP19035 controller is intended to be used for
applications providing up to 20A of output currents
across a wide input voltage range, up to 30V.
The SHDN input is used to turn the device on and off.
While turned off, the current consumption is minimized.
The MCP19035 offers a Power Good feature
(PWRGD), enabling fault detection and simplifying
sequencing.
Package Types
PWRGD
* Includes Exposed Thermal Pad (EP); see
MCP19035
MCP19035
3x3 DFN*
SHDN
1
FB
2
EP
COMP
3
11
V
4
IN
5
10
HDRV
PHASE
9
BOOT
8
7 LDRV
+V
6
CC
Table
3-1.
DS22326B-page 1

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Summary of Contents for Microchip Technology MCP19035

  • Page 1 • Integrated Synchronous MOSFET Drivers design. • Multiple Dead-Time Options The MCP19035 controller is intended to be used for • Internal Blocking Device for Bootstrap Circuit applications providing up to 20A of output currents • Integrated Current Sense Capability for Short across a wide input voltage range, up to 30V.
  • Page 2: Vin

    MCP19035 Typical Application MCP19035 SHDN BOOT BOOT HDRV PWRGD PHASE COMP LDRV  2012-2013 Microchip Technology Inc. DS22326B-page 2...
  • Page 3: Table Of Contents

    Ramp Signal Amplitude Note 1 RAMP Reference Voltage Reference Voltage Generator Ensured by design. Not production tested. Note 1: Limited by the maximum power dissipation of the case. Possibility to be adjusted for high volumes.  2012-2013 Microchip Technology Inc. DS22326B-page 3...
  • Page 4: Vboot

    LDRV Rise Time — = 1.0 nF, Note 1 LOAD Ensured by design. Not production tested. Note 1: Limited by the maximum power dissipation of the case. Possibility to be adjusted for high volumes.  2012-2013 Microchip Technology Inc. DS22326B-page 4...
  • Page 5: Note 1

    +150 °C J-MAX Operating Temperature Range — +125 °C Storage Temperature Range — +150 °C Thermal Package Resistances  Thermal Resistance, 10L-3x3 DFN — 53.3 — °C/W Typical 4-Layer board with interconnecting vias  2012-2013 Microchip Technology Inc. DS22326B-page 5...
  • Page 6 MCP19035 NOTES:  2012-2013 Microchip Technology Inc. DS22326B-page 6...
  • Page 7: Input Voltage Range Vin

    = 300 kHz -2.0 0.75 = 600 kHz -4.0 -6.0 0.25 -8.0 -10.0 Junction Temperature (°C) Junction Temperature (°C) FIGURE 2-3: Relative Oscillator FIGURE 2-6: LDO Regulator Dropout Frequency Variation vs. Temperature. Voltage vs. Temperature.  2012-2013 Microchip Technology Inc. DS22326B-page 7...
  • Page 8 FIGURE 2-11: High-Side Overcurrent Variation vs. Temperature. Threshold vs. Temperature. Rising -100 Falling -200 Junction Temperature (°C) Junction Temperature (°C) FIGURE 2-9: UVLO Thresholds vs. FIGURE 2-12: Low-Side Overcurrent Temperature. Threshold vs. Temperature.  2012-2013 Microchip Technology Inc. DS22326B-page 8...
  • Page 9 Variation vs. Temperature. vs. Temperature. PWRGD = High PWRGD = Low Junction Temperature (°C) Junction Temperature (°C) FIGURE 2-15: LDRV P-Ch R Relative FIGURE 2-18: PG Thresholds Voltage vs. DSon Variation vs. Temperature. Temperature.  2012-2013 Microchip Technology Inc. DS22326B-page 9...
  • Page 10 MCP19035 NOTES:  2012-2013 Microchip Technology Inc. DS22326B-page 10...
  • Page 11 Exposed Thermal Pad, must be connected to GND Shutdown Input Pin (SHDN) Power Good Pin (PWRGD) This pin enables or disables the MCP19035 device. The power good pin is an open drain output. This pin is When logic “High” is applied to this pin, the device is pulled low when the output is 90% less than the typical enabled.
  • Page 12 This pin is the high-side N-channel MOSFET (control transistor) gate drive output. The HDRV drive is capable of sourcing and sinking 1A. 3.11 Exposed Thermal Pad (EP) Analog ground and power ground are both connected to this pin.  2012-2013 Microchip Technology Inc. DS22326B-page 12...
  • Page 13: Uvlo

    MCP19035 • Dead-Time optimization options of the MCP19035 DETAILED DESCRIPTION assist in improving the power conversion effi- ciency, when used with high-speed, low Figure of Device Overview Merit MOSFETs. MCP19035 family devices high- • Overcurrent protection circuits in both high and...
  • Page 14 • Soft-start period is active An integrated, precision voltage reference is provided • Undervoltage condition detected by the MCP19035. An external resistor divider is used • Overcurrent condition detected, on either the High to program the converter’s output voltage. The nominal Side or Low Side value of this internal reference voltage is 600 mV.
  • Page 15 MOSFET at 4.5V V high-side overcurrent counter is decreased by one count. If the high-side overcurrent counter reaches a count of 7, a fault condition exists and the MCP19035 This LDO dissipates power within the MCP19035. To turns off both external MOSFETs.
  • Page 16 If Where: the low-side overcurrent counter reaches a count of 7, = Current that passes through the a fault condition exists and the MCP19035 turns off HS MOS High-Side MOSFET both external MOSFETs. After a 60 ms delay, the MCP19035 device will attempt to restart.
  • Page 17 4.11 Soft Start To control the output voltage during start-up, the MCP19035 uses a soft-start circuit that allows the output voltage of the system to monotonically increase. The soft start circuitry allows the output voltage to rise up to the desired regulation limit, typically within 8 ms.
  • Page 18 MCP19035 NOTES:  2012-2013 Microchip Technology Inc. DS22326B-page 18...
  • Page 19 To simplify this design process, an Excel -based design tool is available to support typical applications. EQUATION 5-1: INDUCTOR VALUE This tool is available on the MCP19035 product web site. Refer to AN1452 – “Using the MCP19035   ...
  • Page 20 In this case, it is recommended ceramic capacitors with aluminum or polymer electrolytic capacitors to reach the recommended value.  2012-2013 Microchip Technology Inc. DS22326B-page 20...
  • Page 21 Their performance will directly impact the efficiency and reliability of the EQUATION 5-11: SWITCHING LOSSES FOR regulator. HIGH-SIDE MOSFET The MCP19035 synchronous buck controller offers an  integrated, logic-level MOSFET driver, and is capable   ...
  • Page 22 = Allowable Gate Drive Voltage Droop (V) DROOP It is recommended that the voltage droop does not exceed 50 mV. A low ESR, ceramic capacitor, rated at least 16 V , is recommended.  2012-2013 Microchip Technology Inc. DS22326B-page 22...
  • Page 23 FEEDBACK LOOP COMPENSATION The frequencies for pole and zero are determined using Equation 5-20: Since the MCP19035 implements a Voltage-Mode PWM control, a Type-III compensation network is EQUATION 5-20: POLE AND ZERO recommended. Correct placing of poles and zeros FREQUENCIES require analysis of the Bode plots for the buck converter power train.
  • Page 24 A at crossover frequency ZERO PTco ). Typically, this crossover frequency occurs between F and F (see Figure 5-3). EQUATION 5-24: POLE GAIN     ------------------------------------  POLE  2012-2013 Microchip Technology Inc. DS22326B-page 24...
  • Page 25  to the interactions between poles and zeros, it is highly --------------------------- - recommended to use the design tool provided by Microchip Technology Inc. to design and analyze the The value of the resistor R is estimated using compensation network.
  • Page 26 MOSFETs at low input voltage. Additional care must be exercised when this alternative schematic is used to minimize the input voltage ripple/noise. The internal circuitry of the MCP19035 may be affected by the ripple/noise present on the V pin. The R...
  • Page 27 This example illustrates the step-by-step design proce- dure for a 12V to 1.8V synchronous buck converter using the MCP19035 controller. To minimize the design effort, Microchip provides a design tool that is used to calculate the component values. See AN1452 - “Using the MCP19035 Synchronous Buck Converter Design Tool”...
  • Page 28 ------------------------------------------------------ -     G Total   IN Max The maximum Total Gate Charge (Q ) at 4.5V G(Total) should be lower than 12 nC (calculated for 10A output current).  2012-2013 Microchip Technology Inc. DS22326B-page 28...
  • Page 29 These thresholds are 480 mV (typical) for high-side for the PCB layout: and 180 mV (typical) for the low-side. The peak current • The exposed pad of MCP19035 DFN case is the for the high-side is: only connection to the internal device ground.
  • Page 30 MCP19035 • For double layer boards, a single ground plane near the MCP19035 case and connect these (usually the bottom) is recommended. components to a low noise ground (signal ground). • Use short, wide traces for the MOSFET’s gate drive connection (LDRV and HDRV signals).
  • Page 31 Figures 6-2 show the difference between PHASE node voltage with and without this resistor. FIGURE 6-2: SW (PHASE) Node With Boot Capacitor Series Resistor. FIGURE 6-3: SW (PHASE) Node Without Boot Capacitor Series Resistor.  2012-2013 Microchip Technology Inc. DS22326B-page 31...
  • Page 32 22PF PGND PGND MCP87050 HDRV 10 SHDN PHASE 1.5PH BOOT 8 COMP VOUT 8.2k 0.33PF 6.8nF LDRV MCP87022 100PF 100PF 100PF 100PF 100PF PWRGD 68pF MCP19035 100k 4.7PF PGND PGND PGND PGND 1.2nF SGND PGND SGND FIGURE 6-4: Schematic Diagram.
  • Page 33 Panasonic - ECG ERJ-3EKF1004V Res. 1M Ohm 1/10W 1% 0603 SMD 100 kΩ Panasonic - ECG ERJ-3EKF1003V Res. 100k Ohm 1/10W 1% 0603 SMD Microchip High Speed Synchronous MCP19035-AAABE/MF Technology Inc. Buck Controller  2012-2013 Microchip Technology Inc. DS22326B-page 33...
  • Page 34 MCP19035 NOTES:  2012-2013 Microchip Technology Inc. DS22326B-page 34...
  • Page 35 In the event the full Microchip part number cannot be marked on one line, it will Note: be carried over to the next line, thus limiting the number of available characters for customer-specific information.  2012-2013 Microchip Technology Inc. DS22326B-page 35...
  • Page 36 MCP19035 Note: For the most current package drawings, please see the Microchip Packaging Specification located at http://www.microchip.com/packaging  2012-2013 Microchip Technology Inc. DS22326B-page 36...
  • Page 37 MCP19035 Note: For the most current package drawings, please see the Microchip Packaging Specification located at http://www.microchip.com/packaging  2012-2013 Microchip Technology Inc. DS22326B-page 37...
  • Page 38 MCP19035 Note: For the most current package drawings, please see the Microchip Packaging Specification located at http://www.microchip.com/packaging  2012-2013 Microchip Technology Inc. DS22326B-page 38...
  • Page 39 600 kHz Switching Frequency mation” option markings. 11. Updated the Product Identification System page with the 600 kHz Switching Frequency option marking information. Revision A (November 2012) • Original Release of this Document.  2012-2013 Microchip Technology Inc. DS22326B-page 39...
  • Page 40 MCP19035 NOTES:  2012-2013 Microchip Technology Inc. DS22326B-page 40...
  • Page 41 MCP19035 PRODUCT IDENTIFICATION SYSTEM To order or obtain information, e.g., on pricing or delivery, refer to the factory or the listed sales office Examples: PART NO. MCP19035-AAAAE/MF: 300 kHz Switching Freq., Device Switching Reference Dead Temperature Package LDRV OC 600 mV V...
  • Page 42 MCP19035 NOTES:  2012-2013 Microchip Technology Inc. DS22326B-page 42...
  • Page 43 Total Endurance, TSHARC, UniWinDriver, WiperLock, ZENA and Z-Scale are trademarks of Microchip Technology Incorporated in the U.S.A. and other countries. SQTP is a service mark of Microchip Technology Incorporated in the U.S.A. GestIC and ULPP are registered trademarks of Microchip Technology Germany II GmbH &...
  • Page 44 Thailand - Bangkok Tel: 86-29-8833-7252 Tel: 66-2-694-1351 Toronto Fax: 86-29-8833-7256 Fax: 66-2-694-1350 Mississauga, Ontario, Canada China - Xiamen Tel: 905-673-0699 Tel: 86-592-2388138 Fax: 905-673-6509 Fax: 86-592-2388130 China - Zhuhai Tel: 86-756-3210040 11/29/12 Fax: 86-756-3210049  2012-2013 Microchip Technology Inc. DS22316B-page 44...

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