Dual Output Step-Up/Inverting DC/DC Converter
The XC9519 series is a 2 channel (step-up and inverting) DC/DC converter IC. One DC/DC converter is a step-up DC/DC and the other is an inverting DC/DC converter. The step-up converter compares a built-in reference voltage 1.0V to the FBP voltage (±1.5%) and a positive output voltage can be set freely with the external components up to 18V. The inverting DC/DC converter compares a difference between a reference voltage and the FBN voltage (±1.5%) to the GND, then a negative output voltage can be set until -15V with the external components.
With a 1.2MHz frequency, the size of the external components can be reduced. As for operation mode, the device can be selected to use PWM control or automatic PWM/PFM switching control by the MODE pin. In the automatic PWM/PFM switching control mode, control switches from PWM to PFM during light loads. The series is highly efficient from light loads through to large output currents. In the PWM control mode, noise is easily reduced since the frequency is fixed. The control mode can be selected for each application. The soft start and current control functions are internally optimized.
During stand-by, all circuits in the IC are shutdown to reduce current consumption to as low as 1.0μA or less. The device includes a gate control pin for the P-channel MOSFET which is used for a load disconnection at the stand-by mode. The GAINP and GAINN pins are used for loop compensation in order to optimize load transient response. With the built-in UVLO (Under Voltage Lock Out) function, the internal driver transistor is forced OFF when input voltage becomes 2.2V or lower.
|Oct 18, 2011||
|Dual Output Step-Up/Inverting DC/DC Converter XC9519 Series|
Typical Application Circuit
|Positive Output Voltage||4.0V～18.0V(Accuracy ±1.5%@25℃)|
|Negative Output Voltage||-15.0V～-4.0V(Accuracy ±1.5%@25℃)|
|Soft-Start Circuit Built-In:||Step-Up DC/DC converter 2.5ms (TYP.)
Inverting DC/DC converter 2.2ms (TYP.)
|Protection Circuits||Over Current Limit (Integral Latching),Short Circuit Protection Latching,UVLO,Thermal Shut Down,Over Voltage Protection|
|Function Addition||Control Pin,Load disconnect Pin,Phase Compensation Pin,Ceramic Capacitor Compatible|
|Operating Ambient Temperature||-40℃～+85℃|
|Environmentally Friendly||EU RoHS compliant, Pb free|
|Package||QFN-24||Number of Pins||24|
|Pcs/Reel||1,000||Package Size(mm)||4.0 x 4.0 x 0.75|
What does the standby mode mean in the case of the multi channel IC?
It means the state where the entire IC has been turned off. For Torex products, it means that the pin voltages of EN1 and EN2 are both 0V.
What is the soft-start function?
The function to soften the rise to prevent the inrush current.
What does CL mean?
Load capacitor. Other companies often refer to it as COUT.
What 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.
What does the FB product mean?
An IC for which any output voltage can be set by the reference voltage of the FB pins and the external dividing resistor. The output voltage is determined by the RFB1 and RFB2 values, using the following formula: VOUT = Vref × (RFB1 + RFB2)/RFB2
How does UVLO (under voltage lockout) work?
This circuit forcibly turns off the driver transistor when VIN drops below the UVLO voltage. If the input voltage recovers to the value which is equal to the specified value or more, UVLO will be released to resume the switching operation. It is resumed by the soft-start function. The paused state by UVLO is not the shutdown. The pulse output is stopped, but the internal circuit is operating.