When a load draws more current than a source can give
There is a way, but it only works if your load is intermittent. You can use your source to charge up an electrolytic capacitor. When your load draws current, it'll draw from both the source and the capacitor at the same time, providing far more available current but only for short duration. Depending upon the current/duration you require, you may need to tweak the capacitor's charging rate or discharge rate, whether by capacitor selection and/or adding series resistance to the capacitor.