MAX17491 查看數據表（PDF） - Maxim Integrated

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MAX17491

Single-Phase Synchronous MOSFET Driver

Maxim Integrated 

Single-Phase Synchronous MOSFET Driver

Typical Operating Characteristics (continued)

(Circuit of Figure 1, VDD = 5V, CDH = 3nF, CDL = 3nF, TA = +25°C, unless otherwise noted.)

VPWM

VDL

VLX

SWITCHING WAVEFORMS

(PWM = MID TO LOW TO MID)

MAX17491 toc11

5V

5V/div

0

5V

5V/div

0

0

10V/div

0

VDH

10V/div

VPWM

VDL

VLX

VDH

SWITCHING WAVEFORMS

(PWM = HIGH TO MID TO HIGH)

MAX17491 toc12

5V

5V/div

0

0

5V/div

10V

10V/div

0

15V

10V/div

0

Pin Description

PIN

NAME

FUNCTION

1

BST

Boost Flying-Capacitor Connection. Gate-drive power supply for DH high-side gate driver. Connect a

0.1μF or 0.22μF capacitor between BST and LX.

PWM Input. Noninverting DH control input from the controller IC:

Logic-high: DH = high (BST), DL = low (PGND).

Midlevel: After the midlevel hold time expires, the controller enters standby mode. DH and DL pulled

2

PWM

low.

Logic-low: DH = low (LX), DL = high (VDD) when SKIP = high.

Internal pullup and pulldown resistors create the midlevel and prevent the controller from triggering an

on-time if this input is left unconnected (not soldered properly) or driven by a high impedance.

3

GND Power Ground for the DL Gate Drivers and Analog Ground. Connect exposed pad to GND.

4

DL PWM Low-Side Gate-Driver Output. Swings between GND and VDD. DL forced high in shutdown.

5

VDD

Supply Voltage Input for the DL Gate Drivers. Connect to 4.2V to 5.5V supply and bypass to GND with a

1μF ceramic capacitor.

Active-Low Pulse-Skipping Mode. Enable pulse-skipping mode (zero-crossing comparator enabled) when

the driver is operating in SKIP mode:

6

SKIP

SKIP = VDD PWM mode

SKIP = GND skip mode

An internal pulldown current pulls the controller into the low-power pulse-skipping state if this input is

left unconnected (not soldered properly) or driven by a high impedance.

7

LX

Switching Node and Inductor Connection. Low-power supply for the DH high-side gate driver. LX

connects to the skip-mode zero-crossing comparator.

8

DH External High-Side n-Channel MOSFET Gate-Driver Output. Swings between LX and BST.

—

EP Exposed Pad. Connect to ground through multiple vias to reduce the thermal impedance.

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