It's no surprise why investors love Dividend Kings -- they're stocks that have grown their dividends for at least 50 years on end without fail. With such reliable track records, it's an easy affair to invest a relatively small amount of money up front and then watch the payout grow year after year -- and that's why they're excellent options for generating passive income from your portfolio. 

Let's take a look at a pair of those Dividend Kings that shouldn't take too long to ramp up to providing you with an annual passive income of $250 after making an initial investment that's likely within your reach today. 

1. Abbott Laboratories

Abbott Laboratories (ABT 1.91%) is a leading option for passive income investors, thanks to its perpetually rising dividend and its relatively low level of risk. Its forward dividend yield of around 1.8% isn't going to make you rich anytime soon, but the low yield is mitigated by the company's long-standing commitment to dividend growth spanning more than 50 years. Its payout rose by 82.1% in the last five years alone.

To accomplish that pace of dividend hikes, the company sells a massive mix of products, including ones you're probably familiar with, like the BinaxNow rapid antigen tests for COVID-19, not to mention more esoteric products, like specialized stents for heart surgery.

Such a diversified product base means that its dividend is more secure than other dividend stocks. In numbers, Abbott's net income in 2021 was more than $7 billion, though its free cash flow (FCF) was even higher, at above $8.6 billion -- and it only paid out around 42% of its net income as dividends, so there's plenty of room to keep hiking the payments. Plus, it means that the longer you're willing to wait, the more likely you are to accumulate a significant quarterly income stream from your shares.

If you're looking to make a relatively small sum of $250 per year from your shares, you'll "only" need to invest around $13,440 up front. Most of us don't have that much lying around, so a better approach to generate the same amount of income is to invest a smaller sum and then wait for the dividend hikes to add up over time. Over the last five years, Abbott's dividend rose at a compound annual growth rate (CAGR) of 10.9%.

That means if you were to invest around $8,064 today, it would yield you $150 in dividends per year, and if we (quite reasonably) assume that your payout will grow by at least the same CAGR moving forward, you'd only need to hold your shares for about five years before you'd be making just over $251 annually. Not too bad of a return for just waiting around. 

2. Johnson & Johnson 

Much like Abbott Labs, Johnson & Johnson (JNJ 3.69%) is a huge, diversified healthcare company that develops and sells medicines, medical devices, and consumer health products like Band-Aids and moisturizers. Many of its products are key for consumers to live happily and healthily, and the business is stable and predictable enough for Warren Buffett himself to have a position in it.

But with the planned spinoff of its consumer health goods division, it'll soon be devoted entirely to making new drugs and devices, which could drive additional growth. For reference, its trailing-12-month revenue expanded by only 43% in the past 10 years, reaching above $96 billion, so the next 10 years could be better for investors.

That should make it an even more lucrative investment for those seeking passive income. And with a payout ratio of 61% and 2021 net income of above $20.8 billion, there's plenty of overhead for more additions to its quarterly dividend.

Right now, its forward dividend yield is a hair over 2.5%, so an investment of just over $9,920 would get you $250 annually, but you can spend even less if you have some patience. Its five-year CAGR is a bit slower than Abbott's, at near 6.1%. So with the more manageable sum of $5,952 worth of its shares today, yielding $150 annually right off the bat, it'd take around nine years for your dividend to grow to become $250.

Of course, if you're willing to wait even longer, you could get the same amount of income with an even smaller investment up front.