XC9106 Series

Variable Output Voltage Step-Up DC/DC Controllers

The XC9106 series are step-up DC/DC controller ICs with an externally applied reference voltage (Vref).

Output voltage will be set with external resistors (RFB1 and RFB2) and Vref value. The series make it easy to control output voltage externally and are suited to software applications that need to vary voltage, such as LCD power supply for PDA.

Output will be stable no matter which load capacitors are used but if a low ESR capacitor is used, RSENSE of about 0.1Ω will be required and phase compensation will be achieved. This makes the use of ceramic capacitors much easier, and allows for lower output ripple and reduced PCB area requirements. Tantalum and electrolytic capacitors can also be used, in which case, RSENSE becomes unnecessary.

Oscillation frequencies of high clock, low ripple 300kHz and low quiescent current 100kHz are available.

Typical Application Circuit


Input Voltage Range 0.9V~10V
Power Supply Voltage Range 1.8V~10.0V and more than Vref+0.7V
Oscillation Frequency 300kHz,100kHz±15%
Output Current More than 30mA
Control PWM/PFM Auto
High Efficiency 85%(TYP.)
Stand-by Current ISTB=1.0μA(MAX.)
Load Capacitors Low ESR capacitors compatible



Technical Document

Quality Reports


QuestionWhat is the soft-start function?

The function to soften the rise to prevent the inrush current.

QuestionWhat is the standby current?

The current that flows through the IC in the standby mode. The standby mode means the state where the IC has been turned off by the CE function.

QuestionWhat is PFM control and PWM control?

PFM control is a method to control the output current by maintaining a constant pulse width, and increasing and decreasing the OFF time according to the output current. Since the PWM control adjusts the pulse width of the ON time to control the output current, the cycle of the ON and OFF time becomes constant, which increases the efficiency during a heavy load. The current consumption during a heavy loading and light load is controlled by switching to PWM control when the output current is high, and to PFM control when the output current is low.

QuestionHow does the GO function of DC/DC converters work? Does it work just like a regulator?

Torex regard the PWM/PFM automatic switch control function as Green Operation (GO) in the case of DC/DC. The GO function is defined as the switching operation between the PFM mode for a small output current and the PWM mode for a large output current. The PFM control method controls the output current by increasing and decreasing the fall time according to the output current while keeping a pulse width. The PWM control method controls the output current by adjusting the pulse width of the rise time, which keeps the rise/fall time interval constant and increases the efficiency at a heavy load. By switching between the PFM control for a small output current and the PWM control for a large output current, the quiescent current can be controlled for both of heavy and light loads.