PDF《TPS40170 4.5V 至60V 宽输入同步 PWM 降压控制器》

32 3 TPS40170 www.ti.com.cn ZHCS155B CNOVEMBER 2013CREVISED DECEMBER

2014 Copyright ? 2013C2014, Texas Instruments Incorporated

5 Pin Configuration and Functions RGY PACKAGE QFN-20 (Top View) Pin Functions PIN I/O DESCRIPTION NAME NO. AGND

9 ― Analog signal ground. This pin must be electrically connected to power ground PGND externally. BOOT

18 O Boot capacitor node for high-side FET gate driver. The boot capacitor is connected from this pin to SW. COMP

8 O Output of the internal error amplifier. The feedback loop compensation network is connected from this pin to the FB pin. ENABLE

1 I This pin must be high for the device to be enabled. If this pin is pulled low, the device is put in a low- power consumption shutdown mode. FB

7 I Negative input to the error amplifier. The output voltage is fed back to this pin through a resistor divider network. HDRV

17 O Gate driver output for the high-side FET. ILIM

12 I A resistor from this pin to PGND sets the overcurrent limit. This pin provides source current used for overcurrent protection threshold setting. LDRV

14 O Gate driver output for the low-side FET. Also, a resistor from this pin to PGND sets the multiplier factor to determine short-circuit current limit. If no resistor is present the multiplier defaults to

7 times the ILIM pin voltage. M/S

3 I Master or slave mode selector pin for frequency synchronization. This pin must be tied to VIN for master mode. In the slave mode this pin must be tied to AGND or left floating. If the pin is tied to AGND, the device synchronizes with a 180° phase shift. If the pin is left floating, the device synchronizes with a 0° phase shift. PGND

13 ― Power ground. This pin must externally connect to the AGND at a single point. PGOOD

11 O Power good indicator. This pin is an open-drain output pin and a

10 kΩ pull-up resistor is recommended to be connected between this pin and VDD. RT

4 I A resistor from this pin to AGND sets the oscillator frequency. Even if operating in slave mode, it is required to have a resistor at this pin to set the free running switching frequency. SS

5 I Soft-start. A capacit........