Orcad--- VPWL_N_TIMES SOURCE

Hello,

I need to create an voltage source that can generate a PWM specifications as shown below.

Voltage level : 12V
0-2s : 100KHz frequency with 2 % dutycycle
2s-4s : duty cycle should slowly increase to 100% by 4s

I have tried creating a PWL file with time and Voltage using VPWL File.., as
0 12
0.0000002 12
0.000000201 0
0.00001 0
0.000010001 12
0.0000102 12
0.000010201 0
0.00002 0

However i am ending up with a huge data.., i have no idea how to use VPWL n time source.

Can any one let me know how to do this in a simple manner.

Thanks,
Lakki.