Details

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BUY UCC28C44D https://www.utsource.net/itm/p/741633.html
BICMOS LOW POWER CURRENT MODE PWM CONTROLLER

Parameter	Symbol	Conditions	Min	Typ	Max	Unit
Input Voltage	VCC		10.5	16.0	30.0	V
Start-Up Current	ISTART	VCC = 17V		1.2		mA
Operating Current	ICC	VCC = 17V		0.8		mA
Supply Undervoltage Lockout	UVLO	VCC falling	9.8		10.5	V
Supply UVLO Hysteresis	VUVLOHYS			0.7		V
Maximum Duty Cycle	DMAX			0.5
Minimum ON-Time	tON(MIN)		1.4			渭s
Minimum OFF-Time	tOFF(MIN)		1.4			渭s
Frequency Clamp Frequency	FCLAMP		100			kHz
ZCD Threshold Voltage	VZCDTH		0.25		0.35	V
ZCD Hysteresis Voltage	VZCDHYST		0.1		0.15	V
Output Drive Capability	IOH/IOHL	fSW = 100kHz, VOUT = 5V	卤200			mA

Instructions for UCC28C44D

1. Power Supply Requirements:

   • Ensure the input voltage (VCC) is within the specified range of 10.5V to 30.0V.
   • The device starts up when VCC rises above the UVLO threshold and shuts down when it falls below the UVLO threshold.

2. Operating Current:

   • The operating current (ICC) at a typical supply voltage of 17V is around 0.8mA.

3. Frequency Control:

   • Set the frequency clamp to limit the switching frequency to a maximum of 100kHz to ensure stable operation.

4. Duty Cycle Limitation:

   • The maximum duty cycle is limited to 50% to prevent excessive power dissipation.

5. Minimum ON/OFF Time:

   • Ensure that the minimum on-time and off-time are not less than 1.4渭s to avoid potential instability in the control loop.

6. Zero Current Detection (ZCD):

   • Use the ZCD feature to synchronize the switching with the zero crossing of the current to minimize switching losses.

7. Output Drive:

   • The output driver can source and sink up to 卤200mA, suitable for driving MOSFETs directly.

8. Layout Considerations:

   • Pay attention to PCB layout to minimize noise coupling and ensure reliable operation. Keep high-current paths short and direct.

9. Thermal Management:

   • Ensure adequate heat sinking if operating at higher power levels or in high ambient temperatures to maintain reliability.

10. Protection Features:

    • The device includes supply undervoltage lockout (UVLO) and other protection mechanisms to safeguard against abnormal operating conditions.

(For reference only)